1 files changed, 42 insertions, 13 deletions

diff --git a/fs/btrfs/transaction.c b/fs/btrfs/transaction.c
index cf8706ce85a..fd319b2ecd8 100644
--- a/fs/btrfs/transaction.c
+++ b/fs/btrfs/transaction.c
@@ -51,17 +51,41 @@ static noinline void switch_commit_root(struct btrfs_root *root)
 }
 
 static inline int can_join_transaction(struct btrfs_transaction *trans,
-				       int type)
+				       unsigned int type)
 {
 	return !(trans->in_commit &&
-		 type != TRANS_JOIN &&
-		 type != TRANS_JOIN_NOLOCK);
+		 (type & TRANS_EXTWRITERS));
+}
+
+static inline void extwriter_counter_inc(struct btrfs_transaction *trans,
+					 unsigned int type)
+{
+	if (type & TRANS_EXTWRITERS)
+		atomic_inc(&trans->num_extwriters);
+}
+
+static inline void extwriter_counter_dec(struct btrfs_transaction *trans,
+					 unsigned int type)
+{
+	if (type & TRANS_EXTWRITERS)
+		atomic_dec(&trans->num_extwriters);
+}
+
+static inline void extwriter_counter_init(struct btrfs_transaction *trans,
+					  unsigned int type)
+{
+	atomic_set(&trans->num_extwriters, ((type & TRANS_EXTWRITERS) ? 1 : 0));
+}
+
+static inline int extwriter_counter_read(struct btrfs_transaction *trans)
+{
+	return atomic_read(&trans->num_extwriters);
 }
 
 /*
  * either allocate a new transaction or hop into the existing one
  */
-static noinline int join_transaction(struct btrfs_root *root, int type)
+static noinline int join_transaction(struct btrfs_root *root, unsigned int type)
 {
 	struct btrfs_transaction *cur_trans;
 	struct btrfs_fs_info *fs_info = root->fs_info;
@@ -99,6 +123,7 @@ loop:
 		}
 		atomic_inc(&cur_trans->use_count);
 		atomic_inc(&cur_trans->num_writers);
+		extwriter_counter_inc(cur_trans, type);
 		cur_trans->num_joined++;
 		spin_unlock(&fs_info->trans_lock);
 		return 0;
@@ -131,6 +156,7 @@ loop:
 	}
 
 	atomic_set(&cur_trans->num_writers, 1);
+	extwriter_counter_init(cur_trans, type);
 	cur_trans->num_joined = 0;
 	init_waitqueue_head(&cur_trans->writer_wait);
 	init_waitqueue_head(&cur_trans->commit_wait);
@@ -307,7 +333,7 @@ static int may_wait_transaction(struct btrfs_root *root, int type)
 }
 
 static struct btrfs_trans_handle *
-start_transaction(struct btrfs_root *root, u64 num_items, int type,
+start_transaction(struct btrfs_root *root, u64 num_items, unsigned int type,
 		  enum btrfs_reserve_flush_enum flush)
 {
 	struct btrfs_trans_handle *h;
@@ -320,7 +346,7 @@ start_transaction(struct btrfs_root *root, u64 num_items, int type,
 		return ERR_PTR(-EROFS);
 
 	if (current->journal_info) {
-		WARN_ON(type != TRANS_JOIN && type != TRANS_JOIN_NOLOCK);
+		WARN_ON(type & TRANS_EXTWRITERS);
 		h = current->journal_info;
 		h->use_count++;
 		WARN_ON(h->use_count > 2);
@@ -366,7 +392,7 @@ again:
 	 * If we are ATTACH, it means we just want to catch the current
 	 * transaction and commit it, so we needn't do sb_start_intwrite(). 
 	 */
-	if (type < TRANS_JOIN_NOLOCK)
+	if (type & __TRANS_FREEZABLE)
 		sb_start_intwrite(root->fs_info->sb);
 
 	if (may_wait_transaction(root, type))
@@ -429,7 +455,7 @@ got_it:
 	return h;
 
 join_fail:
-	if (type < TRANS_JOIN_NOLOCK)
+	if (type & __TRANS_FREEZABLE)
 		sb_end_intwrite(root->fs_info->sb);
 	kmem_cache_free(btrfs_trans_handle_cachep, h);
 alloc_fail:
@@ -677,12 +703,13 @@ static int __btrfs_end_transaction(struct btrfs_trans_handle *trans,
 		}
 	}
 
-	if (trans->type < TRANS_JOIN_NOLOCK)
+	if (trans->type & __TRANS_FREEZABLE)
 		sb_end_intwrite(root->fs_info->sb);
 
 	WARN_ON(cur_trans != info->running_transaction);
 	WARN_ON(atomic_read(&cur_trans->num_writers) < 1);
 	atomic_dec(&cur_trans->num_writers);
+	extwriter_counter_dec(cur_trans, trans->type);
 
 	smp_mb();
 	if (waitqueue_active(&cur_trans->writer_wait))
@@ -1625,6 +1652,8 @@ int btrfs_commit_transaction(struct btrfs_trans_handle *trans,
 		spin_unlock(&root->fs_info->trans_lock);
 	}
 
+	extwriter_counter_dec(cur_trans, trans->type);
+
 	if (!btrfs_test_opt(root, SSD) &&
 	    (now < cur_trans->start_time || now - cur_trans->start_time < 1))
 		should_grow = 1;
@@ -1641,13 +1670,13 @@ int btrfs_commit_transaction(struct btrfs_trans_handle *trans,
 		prepare_to_wait(&cur_trans->writer_wait, &wait,
 				TASK_UNINTERRUPTIBLE);
 
-		if (atomic_read(&cur_trans->num_writers) > 1)
-			schedule_timeout(MAX_SCHEDULE_TIMEOUT);
+		if (extwriter_counter_read(cur_trans) > 0)
+			schedule();
 		else if (should_grow)
 			schedule_timeout(1);
 
 		finish_wait(&cur_trans->writer_wait, &wait);
-	} while (atomic_read(&cur_trans->num_writers) > 1 ||
+	} while (extwriter_counter_read(cur_trans) > 0 ||
 		 (should_grow && cur_trans->num_joined != joined));
 
 	ret = btrfs_flush_all_pending_stuffs(trans, root);
@@ -1831,7 +1860,7 @@ int btrfs_commit_transaction(struct btrfs_trans_handle *trans,
 	put_transaction(cur_trans);
 	put_transaction(cur_trans);
 
-	if (trans->type < TRANS_JOIN_NOLOCK)
+	if (trans->type & __TRANS_FREEZABLE)
 		sb_end_intwrite(root->fs_info->sb);
 
 	trace_btrfs_transaction_commit(root);