4 files changed, 27 insertions, 6 deletions

diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h
index 9b02596..62499dd 100644
--- a/fs/btrfs/ctree.h
+++ b/fs/btrfs/ctree.h
@@ -518,6 +518,7 @@ struct btrfs_fs_info {
 
 	u64 generation;
 	u64 last_trans_committed;
+	u64 open_ioctl_trans;
 	unsigned long mount_opt;
 	u64 max_extent;
 	u64 max_inline;
diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c
index 224da28..0b63c3c 100644
--- a/fs/btrfs/ioctl.c
+++ b/fs/btrfs/ioctl.c
@@ -715,7 +715,12 @@ long btrfs_ioctl_trans_start(struct file *file)
 		ret = -EINPROGRESS;
 		goto out;
 	}
-	trans = btrfs_start_transaction(root, 0);
+
+	mutex_lock(&root->fs_info->trans_mutex);
+	root->fs_info->open_ioctl_trans++;
+	mutex_unlock(&root->fs_info->trans_mutex);
+
+	trans = btrfs_start_ioctl_transaction(root, 0);
 	if (trans)
 		file->private_data = trans;
 	else
@@ -745,6 +750,11 @@ long btrfs_ioctl_trans_end(struct file *file)
 	}
 	btrfs_end_transaction(trans, root);
 	file->private_data = 0;
+
+	mutex_lock(&root->fs_info->trans_mutex);
+	root->fs_info->open_ioctl_trans--;
+	mutex_unlock(&root->fs_info->trans_mutex);
+
 out:
 	return ret;
 }
diff --git a/fs/btrfs/transaction.c b/fs/btrfs/transaction.c
index cf73342..a2c821e 100644
--- a/fs/btrfs/transaction.c
+++ b/fs/btrfs/transaction.c
@@ -152,14 +152,14 @@ static void wait_current_trans(struct btrfs_root *root)
 }
 
 struct btrfs_trans_handle *start_transaction(struct btrfs_root *root,
-					     int num_blocks, int join)
+					     int num_blocks, int wait)
 {
 	struct btrfs_trans_handle *h =
 		kmem_cache_alloc(btrfs_trans_handle_cachep, GFP_NOFS);
 	int ret;
 
 	mutex_lock(&root->fs_info->trans_mutex);
-	if (!join)
+	if ((wait == 1 && !root->fs_info->open_ioctl_trans) || wait == 2)
 		wait_current_trans(root);
 	ret = join_transaction(root);
 	BUG_ON(ret);
@@ -180,14 +180,21 @@ struct btrfs_trans_handle *start_transaction(struct btrfs_root *root,
 struct btrfs_trans_handle *btrfs_start_transaction(struct btrfs_root *root,
 						   int num_blocks)
 {
-	return start_transaction(root, num_blocks, 0);
+	return start_transaction(root, num_blocks, 1);
 }
 struct btrfs_trans_handle *btrfs_join_transaction(struct btrfs_root *root,
 						   int num_blocks)
 {
-	return start_transaction(root, num_blocks, 1);
+	return start_transaction(root, num_blocks, 0);
 }
 
+struct btrfs_trans_handle *btrfs_start_ioctl_transaction(struct btrfs_root *r,
+							 int num_blocks)
+{
+	return start_transaction(r, num_blocks, 2);
+}
+
+
 static noinline int wait_for_commit(struct btrfs_root *root,
 				    struct btrfs_transaction *commit)
 {
@@ -247,7 +254,8 @@ harder:
 void btrfs_throttle(struct btrfs_root *root)
 {
 	mutex_lock(&root->fs_info->trans_mutex);
-	wait_current_trans(root);
+	if (!root->fs_info->open_ioctl_trans)
+		wait_current_trans(root);
 	mutex_unlock(&root->fs_info->trans_mutex);
 
 	throttle_on_drops(root);
diff --git a/fs/btrfs/transaction.h b/fs/btrfs/transaction.h
index f5adb23..2c73cae 100644
--- a/fs/btrfs/transaction.h
+++ b/fs/btrfs/transaction.h
@@ -83,6 +83,8 @@ struct btrfs_trans_handle *btrfs_start_transaction(struct btrfs_root *root,
 						   int num_blocks);
 struct btrfs_trans_handle *btrfs_join_transaction(struct btrfs_root *root,
 						   int num_blocks);
+struct btrfs_trans_handle *btrfs_start_ioctl_transaction(struct btrfs_root *r,
+						   int num_blocks);
 int btrfs_write_and_wait_transaction(struct btrfs_trans_handle *trans,
 				     struct btrfs_root *root);
 int btrfs_commit_tree_roots(struct btrfs_trans_handle *trans,