---

yaml
---
r: 260885
b: refs/heads/master
c: fdb5eff
h: refs/heads/master
i:
  260883: a78af42
v: v3

[refs]

@@ -1,2 +1,2 @@
 ---
-refs/heads/master: b5009945be18023942ce28327893c7bc1e58fe54
+refs/heads/master: fdb5effd5c2a7e01dc3a4217bb194e2d3a5b160f

trunk/fs/btrfs/ctree.h

@@ -756,6 +756,8 @@ struct btrfs_space_info {
 				   chunks for this space */
 	unsigned int chunk_alloc:1;	/* set if we are allocating a chunk */
 
+	unsigned int flush:1;		/* set if we are trying to make space */
+
 	unsigned int force_alloc;	/* set if we need to force a chunk
 					   alloc for this space */
 
@@ -766,6 +768,7 @@ struct btrfs_space_info {
 	spinlock_t lock;
 	struct rw_semaphore groups_sem;
 	atomic_t caching_threads;
+	wait_queue_head_t wait;
 };
 
 struct btrfs_block_rsv {

trunk/fs/btrfs/extent-tree.c

@@ -2932,6 +2932,8 @@ static int update_space_info(struct btrfs_fs_info *info, u64 flags,
 	found->full = 0;
 	found->force_alloc = CHUNK_ALLOC_NO_FORCE;
 	found->chunk_alloc = 0;
+	found->flush = 0;
+	init_waitqueue_head(&found->wait);
 	*space_info = found;
 	list_add_rcu(&found->list, &info->space_info);
 	atomic_set(&found->caching_threads, 0);
@@ -3314,6 +3316,14 @@ static int shrink_delalloc(struct btrfs_trans_handle *trans,
 	if (reserved == 0)
 		return 0;
 
+	smp_mb();
+	if (root->fs_info->delalloc_bytes == 0) {
+		if (trans)
+			return 0;
+		btrfs_wait_ordered_extents(root, 0, 0);
+		return 0;
+	}
+
 	max_reclaim = min(reserved, to_reclaim);
 
 	while (loops < 1024) {
@@ -3356,6 +3366,8 @@ static int shrink_delalloc(struct btrfs_trans_handle *trans,
 		}
 
 	}
+	if (reclaimed >= to_reclaim && !trans)
+		btrfs_wait_ordered_extents(root, 0, 0);
 	return reclaimed >= to_reclaim;
 }
 
@@ -3380,15 +3392,36 @@ static int reserve_metadata_bytes(struct btrfs_trans_handle *trans,
 	u64 num_bytes = orig_bytes;
 	int retries = 0;
 	int ret = 0;
-	bool reserved = false;
 	bool committed = false;
+	bool flushing = false;
 
 again:
-	ret = -ENOSPC;
-	if (reserved)
-		num_bytes = 0;
-
+	ret = 0;
 	spin_lock(&space_info->lock);
+	/*
+	 * We only want to wait if somebody other than us is flushing and we are
+	 * actually alloed to flush.
+	 */
+	while (flush && !flushing && space_info->flush) {
+		spin_unlock(&space_info->lock);
+		/*
+		 * If we have a trans handle we can't wait because the flusher
+		 * may have to commit the transaction, which would mean we would
+		 * deadlock since we are waiting for the flusher to finish, but
+		 * hold the current transaction open.
+		 */
+		if (trans)
+			return -EAGAIN;
+		ret = wait_event_interruptible(space_info->wait,
+					       !space_info->flush);
+		/* Must have been interrupted, return */
+		if (ret)
+			return -EINTR;
+
+		spin_lock(&space_info->lock);
+	}
+
+	ret = -ENOSPC;
 	unused = space_info->bytes_used + space_info->bytes_reserved +
 		 space_info->bytes_pinned + space_info->bytes_readonly +
 		 space_info->bytes_may_use;
@@ -3403,8 +3436,7 @@ static int reserve_metadata_bytes(struct btrfs_trans_handle *trans,
 	if (unused <= space_info->total_bytes) {
 		unused = space_info->total_bytes - unused;
 		if (unused >= num_bytes) {
-			if (!reserved)
-				space_info->bytes_reserved += orig_bytes;
+			space_info->bytes_reserved += orig_bytes;
 			ret = 0;
 		} else {
 			/*
@@ -3429,27 +3461,22 @@ static int reserve_metadata_bytes(struct btrfs_trans_handle *trans,
 	 * to reclaim space we can actually use it instead of somebody else
 	 * stealing it from us.
 	 */
-	if (ret && !reserved) {
-		space_info->bytes_reserved += orig_bytes;
-		reserved = true;
+	if (ret && flush) {
+		flushing = true;
+		space_info->flush = 1;
 	}
 
 	spin_unlock(&space_info->lock);
 
-	if (!ret)
-		return 0;
-
-	if (!flush)
+	if (!ret || !flush)
 		goto out;
 
 	/*
 	 * We do synchronous shrinking since we don't actually unreserve
 	 * metadata until after the IO is completed.
 	 */
 	ret = shrink_delalloc(trans, root, num_bytes, 1);
-	if (ret > 0)
-		return 0;
-	else if (ret < 0)
+	if (ret < 0)
 		goto out;
 
 	/*
@@ -3462,11 +3489,11 @@ static int reserve_metadata_bytes(struct btrfs_trans_handle *trans,
 		goto again;
 	}
 
-	spin_lock(&space_info->lock);
 	/*
 	 * Not enough space to be reclaimed, don't bother committing the
 	 * transaction.
 	 */
+	spin_lock(&space_info->lock);
 	if (space_info->bytes_pinned < orig_bytes)
 		ret = -ENOSPC;
 	spin_unlock(&space_info->lock);
@@ -3489,12 +3516,12 @@ static int reserve_metadata_bytes(struct btrfs_trans_handle *trans,
 	}
 
 out:
-	if (reserved) {
+	if (flushing) {
 		spin_lock(&space_info->lock);
-		space_info->bytes_reserved -= orig_bytes;
+		space_info->flush = 0;
+		wake_up_all(&space_info->wait);
 		spin_unlock(&space_info->lock);
 	}
-
 	return ret;
 }