2 files changed, 182 insertions, 185 deletions

diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h
index 6036fdb..0ee679b 100644
--- a/fs/btrfs/ctree.h
+++ b/fs/btrfs/ctree.h
@@ -783,9 +783,6 @@ struct btrfs_free_cluster {
 	/* first extent starting offset */
 	u64 window_start;
 
-	/* if this cluster simply points at a bitmap in the block group */
-	bool points_to_bitmap;
-
 	struct btrfs_block_group_cache *block_group;
 	/*
 	 * when a cluster is allocated from a block group, we put the
diff --git a/fs/btrfs/free-space-cache.c b/fs/btrfs/free-space-cache.c
index 4ab35ea..f03ef97 100644
--- a/fs/btrfs/free-space-cache.c
+++ b/fs/btrfs/free-space-cache.c
@@ -1644,30 +1644,28 @@ __btrfs_return_cluster_to_free_space(
 {
 	struct btrfs_free_space *entry;
 	struct rb_node *node;
-	bool bitmap;
 
 	spin_lock(&cluster->lock);
 	if (cluster->block_group != block_group)
 		goto out;
 
-	bitmap = cluster->points_to_bitmap;
 	cluster->block_group = NULL;
 	cluster->window_start = 0;
 	list_del_init(&cluster->block_group_list);
-	cluster->points_to_bitmap = false;
-
-	if (bitmap)
-		goto out;
 
 	node = rb_first(&cluster->root);
 	while (node) {
+		bool bitmap;
+
 		entry = rb_entry(node, struct btrfs_free_space, offset_index);
 		node = rb_next(&entry->offset_index);
 		rb_erase(&entry->offset_index, &cluster->root);
-		BUG_ON(entry->bitmap);
-		try_merge_free_space(block_group, entry, false);
+
+		bitmap = (entry->bitmap != NULL);
+		if (!bitmap)
+			try_merge_free_space(block_group, entry, false);
 		tree_insert_offset(&block_group->free_space_offset,
-				   entry->offset, &entry->offset_index, 0);
+				   entry->offset, &entry->offset_index, bitmap);
 	}
 	cluster->root = RB_ROOT;
 
@@ -1790,50 +1788,24 @@ int btrfs_return_cluster_to_free_space(
 
 static u64 btrfs_alloc_from_bitmap(struct btrfs_block_group_cache *block_group,
 				   struct btrfs_free_cluster *cluster,
+				   struct btrfs_free_space *entry,
 				   u64 bytes, u64 min_start)
 {
-	struct btrfs_free_space *entry;
 	int err;
 	u64 search_start = cluster->window_start;
 	u64 search_bytes = bytes;
 	u64 ret = 0;
 
-	spin_lock(&block_group->tree_lock);
-	spin_lock(&cluster->lock);
-
-	if (!cluster->points_to_bitmap)
-		goto out;
-
-	if (cluster->block_group != block_group)
-		goto out;
-
-	/*
-	 * search_start is the beginning of the bitmap, but at some point it may
-	 * be a good idea to point to the actual start of the free area in the
-	 * bitmap, so do the offset_to_bitmap trick anyway, and set bitmap_only
-	 * to 1 to make sure we get the bitmap entry
-	 */
-	entry = tree_search_offset(block_group,
-				   offset_to_bitmap(block_group, search_start),
-				   1, 0);
-	if (!entry || !entry->bitmap)
-		goto out;
-
 	search_start = min_start;
 	search_bytes = bytes;
 
 	err = search_bitmap(block_group, entry, &search_start,
 			    &search_bytes);
 	if (err)
-		goto out;
+		return 0;
 
 	ret = search_start;
 	bitmap_clear_bits(block_group, entry, ret, bytes);
-	if (entry->bytes == 0)
-		free_bitmap(block_group, entry);
-out:
-	spin_unlock(&cluster->lock);
-	spin_unlock(&block_group->tree_lock);
 
 	return ret;
 }
@@ -1851,10 +1823,6 @@ u64 btrfs_alloc_from_cluster(struct btrfs_block_group_cache *block_group,
 	struct rb_node *node;
 	u64 ret = 0;
 
-	if (cluster->points_to_bitmap)
-		return btrfs_alloc_from_bitmap(block_group, cluster, bytes,
-					       min_start);
-
 	spin_lock(&cluster->lock);
 	if (bytes > cluster->max_size)
 		goto out;
@@ -1867,9 +1835,9 @@ u64 btrfs_alloc_from_cluster(struct btrfs_block_group_cache *block_group,
 		goto out;
 
 	entry = rb_entry(node, struct btrfs_free_space, offset_index);
-
 	while(1) {
-		if (entry->bytes < bytes || entry->offset < min_start) {
+		if (entry->bytes < bytes ||
+		    (!entry->bitmap && entry->offset < min_start)) {
 			struct rb_node *node;
 
 			node = rb_next(&entry->offset_index);
@@ -1879,10 +1847,27 @@ u64 btrfs_alloc_from_cluster(struct btrfs_block_group_cache *block_group,
 					 offset_index);
 			continue;
 		}
-		ret = entry->offset;
 
-		entry->offset += bytes;
-		entry->bytes -= bytes;
+		if (entry->bitmap) {
+			ret = btrfs_alloc_from_bitmap(block_group,
+						      cluster, entry, bytes,
+						      min_start);
+			if (ret == 0) {
+				struct rb_node *node;
+				node = rb_next(&entry->offset_index);
+				if (!node)
+					break;
+				entry = rb_entry(node, struct btrfs_free_space,
+						 offset_index);
+				continue;
+			}
+		} else {
+
+			ret = entry->offset;
+
+			entry->offset += bytes;
+			entry->bytes -= bytes;
+		}
 
 		if (entry->bytes == 0)
 			rb_erase(&entry->offset_index, &cluster->root);
@@ -1899,6 +1884,11 @@ out:
 	block_group->free_space -= bytes;
 	if (entry->bytes == 0) {
 		block_group->free_extents--;
+		if (entry->bitmap) {
+			kfree(entry->bitmap);
+			block_group->total_bitmaps--;
+			recalculate_thresholds(block_group);
+		}
 		kmem_cache_free(btrfs_free_space_cachep, entry);
 	}
 
@@ -1919,6 +1909,7 @@ static int btrfs_bitmap_cluster(struct btrfs_block_group_cache *block_group,
 	unsigned long found_bits;
 	unsigned long start = 0;
 	unsigned long total_found = 0;
+	int ret;
 	bool found = false;
 
 	i = offset_to_bit(entry->offset, block_group->sectorsize,
@@ -1941,7 +1932,7 @@ again:
 	}
 
 	if (!found_bits)
-		return -1;
+		return -ENOSPC;
 
 	if (!found) {
 		start = i;
@@ -1965,12 +1956,145 @@ again:
 
 	cluster->window_start = start * block_group->sectorsize +
 		entry->offset;
-	cluster->points_to_bitmap = true;
+	rb_erase(&entry->offset_index, &block_group->free_space_offset);
+	ret = tree_insert_offset(&cluster->root, entry->offset,
+				 &entry->offset_index, 1);
+	BUG_ON(ret);
 
 	return 0;
 }
 
 /*
+ * This searches the block group for just extents to fill the cluster with.
+ */
+static int setup_cluster_no_bitmap(struct btrfs_block_group_cache *block_group,
+				   struct btrfs_free_cluster *cluster,
+				   u64 offset, u64 bytes, u64 min_bytes)
+{
+	struct btrfs_free_space *first = NULL;
+	struct btrfs_free_space *entry = NULL;
+	struct btrfs_free_space *prev = NULL;
+	struct btrfs_free_space *last;
+	struct rb_node *node;
+	u64 window_start;
+	u64 window_free;
+	u64 max_extent;
+	u64 max_gap = 128 * 1024;
+
+	entry = tree_search_offset(block_group, offset, 0, 1);
+	if (!entry)
+		return -ENOSPC;
+
+	/*
+	 * We don't want bitmaps, so just move along until we find a normal
+	 * extent entry.
+	 */
+	while (entry->bitmap) {
+		node = rb_next(&entry->offset_index);
+		if (!node)
+			return -ENOSPC;
+		entry = rb_entry(node, struct btrfs_free_space, offset_index);
+	}
+
+	window_start = entry->offset;
+	window_free = entry->bytes;
+	max_extent = entry->bytes;
+	first = entry;
+	last = entry;
+	prev = entry;
+
+	while (window_free <= min_bytes) {
+		node = rb_next(&entry->offset_index);
+		if (!node)
+			return -ENOSPC;
+		entry = rb_entry(node, struct btrfs_free_space, offset_index);
+
+		if (entry->bitmap)
+			continue;
+		/*
+		 * we haven't filled the empty size and the window is
+		 * very large.  reset and try again
+		 */
+		if (entry->offset - (prev->offset + prev->bytes) > max_gap ||
+		    entry->offset - window_start > (min_bytes * 2)) {
+			first = entry;
+			window_start = entry->offset;
+			window_free = entry->bytes;
+			last = entry;
+			max_extent = entry->bytes;
+		} else {
+			last = entry;
+			window_free += entry->bytes;
+			if (entry->bytes > max_extent)
+				max_extent = entry->bytes;
+		}
+		prev = entry;
+	}
+
+	cluster->window_start = first->offset;
+
+	node = &first->offset_index;
+
+	/*
+	 * now we've found our entries, pull them out of the free space
+	 * cache and put them into the cluster rbtree
+	 */
+	do {
+		int ret;
+
+		entry = rb_entry(node, struct btrfs_free_space, offset_index);
+		node = rb_next(&entry->offset_index);
+		if (entry->bitmap)
+			continue;
+
+		rb_erase(&entry->offset_index, &block_group->free_space_offset);
+		ret = tree_insert_offset(&cluster->root, entry->offset,
+					 &entry->offset_index, 0);
+		BUG_ON(ret);
+	} while (node && entry != last);
+
+	cluster->max_size = max_extent;
+
+	return 0;
+}
+
+/*
+ * This specifically looks for bitmaps that may work in the cluster, we assume
+ * that we have already failed to find extents that will work.
+ */
+static int setup_cluster_bitmap(struct btrfs_block_group_cache *block_group,
+				struct btrfs_free_cluster *cluster,
+				u64 offset, u64 bytes, u64 min_bytes)
+{
+	struct btrfs_free_space *entry;
+	struct rb_node *node;
+	int ret = -ENOSPC;
+
+	if (block_group->total_bitmaps == 0)
+		return -ENOSPC;
+
+	entry = tree_search_offset(block_group,
+				   offset_to_bitmap(block_group, offset),
+				   0, 1);
+	if (!entry)
+		return -ENOSPC;
+
+	node = &entry->offset_index;
+	do {
+		entry = rb_entry(node, struct btrfs_free_space, offset_index);
+		node = rb_next(&entry->offset_index);
+		if (!entry->bitmap)
+			continue;
+		if (entry->bytes < min_bytes)
+			continue;
+		ret = btrfs_bitmap_cluster(block_group, entry, cluster, offset,
+					   bytes, min_bytes);
+	} while (ret && node);
+
+	return ret;
+}
+
+/*
  * here we try to find a cluster of blocks in a block group.  The goal
  * is to find at least bytes free and up to empty_size + bytes free.
  * We might not find them all in one contiguous area.
@@ -1984,15 +2108,7 @@ int btrfs_find_space_cluster(struct btrfs_trans_handle *trans,
 			     struct btrfs_free_cluster *cluster,
 			     u64 offset, u64 bytes, u64 empty_size)
 {
-	struct btrfs_free_space *entry = NULL;
-	struct rb_node *node;
-	struct btrfs_free_space *next;
-	struct btrfs_free_space *last = NULL;
 	u64 min_bytes;
-	u64 window_start;
-	u64 window_free;
-	u64 max_extent = 0;
-	bool found_bitmap = false;
 	int ret;
 
 	/* for metadata, allow allocates with more holes */
@@ -2029,134 +2145,19 @@ int btrfs_find_space_cluster(struct btrfs_trans_handle *trans,
 		ret = 0;
 		goto out;
 	}
-again:
-	entry = tree_search_offset(block_group, offset, found_bitmap, 1);
-	if (!entry) {
-		ret = -ENOSPC;
-		goto out;
-	}
-
-	/*
-	 * If found_bitmap is true, we exhausted our search for extent entries,
-	 * and we just want to search all of the bitmaps that we can find, and
-	 * ignore any extent entries we find.
-	 */
-	while (entry->bitmap || found_bitmap ||
-	       (!entry->bitmap && entry->bytes < min_bytes)) {
-		struct rb_node *node = rb_next(&entry->offset_index);
-
-		if (entry->bitmap && entry->bytes > bytes + empty_size) {
-			ret = btrfs_bitmap_cluster(block_group, entry, cluster,
-						   offset, bytes, min_bytes);
-			if (!ret)
-				goto got_it;
-		}
-
-		if (!node) {
-			ret = -ENOSPC;
-			goto out;
-		}
-		entry = rb_entry(node, struct btrfs_free_space, offset_index);
-	}
-
-	/*
-	 * We already searched all the extent entries from the passed in offset
-	 * to the end and didn't find enough space for the cluster, and we also
-	 * didn't find any bitmaps that met our criteria, just go ahead and exit
-	 */
-	if (found_bitmap) {
-		ret = -ENOSPC;
-		goto out;
-	}
-
-	cluster->points_to_bitmap = false;
-	window_start = entry->offset;
-	window_free = entry->bytes;
-	last = entry;
-	max_extent = entry->bytes;
-
-	while (1) {
-		/* out window is just right, lets fill it */
-		if (window_free >= min_bytes)
-			break;
-
-		node = rb_next(&last->offset_index);
-		if (!node) {
-			if (found_bitmap)
-				goto again;
-			ret = -ENOSPC;
-			goto out;
-		}
-		next = rb_entry(node, struct btrfs_free_space, offset_index);
-
-		/*
-		 * we found a bitmap, so if this search doesn't result in a
-		 * cluster, we know to go and search again for the bitmaps and
-		 * start looking for space there
-		 */
-		if (next->bitmap) {
-			if (!found_bitmap)
-				offset = next->offset;
-			found_bitmap = true;
-			last = next;
-			continue;
-		}
-
-		/*
-		 * we haven't filled the empty size and the window is
-		 * very large.  reset and try again
-		 */
-		if (next->offset - (last->offset + last->bytes) > 128 * 1024 ||
-		    next->offset - window_start > (bytes + empty_size) * 2) {
-			entry = next;
-			window_start = entry->offset;
-			window_free = entry->bytes;
-			last = entry;
-			max_extent = entry->bytes;
-		} else {
-			last = next;
-			window_free += next->bytes;
-			if (entry->bytes > max_extent)
-				max_extent = entry->bytes;
-		}
-	}
-
-	cluster->window_start = entry->offset;
-
-	/*
-	 * now we've found our entries, pull them out of the free space
-	 * cache and put them into the cluster rbtree
-	 *
-	 * The cluster includes an rbtree, but only uses the offset index
-	 * of each free space cache entry.
-	 */
-	while (1) {
-		node = rb_next(&entry->offset_index);
-		if (entry->bitmap && node) {
-			entry = rb_entry(node, struct btrfs_free_space,
-					 offset_index);
-			continue;
-		} else if (entry->bitmap && !node) {
-			break;
-		}
-
-		rb_erase(&entry->offset_index, &block_group->free_space_offset);
-		ret = tree_insert_offset(&cluster->root, entry->offset,
-					 &entry->offset_index, 0);
-		BUG_ON(ret);
 
-		if (!node || entry == last)
-			break;
+	ret = setup_cluster_no_bitmap(block_group, cluster, offset, bytes,
+				      min_bytes);
+	if (ret)
+		ret = setup_cluster_bitmap(block_group, cluster, offset,
+					   bytes, min_bytes);
 
-		entry = rb_entry(node, struct btrfs_free_space, offset_index);
+	if (!ret) {
+		atomic_inc(&block_group->count);
+		list_add_tail(&cluster->block_group_list,
+			      &block_group->cluster_list);
+		cluster->block_group = block_group;
 	}
-
-	cluster->max_size = max_extent;
-got_it:
-	ret = 0;
-	atomic_inc(&block_group->count);
-	list_add_tail(&cluster->block_group_list, &block_group->cluster_list);
-	cluster->block_group = block_group;
 out:
 	spin_unlock(&cluster->lock);
 	spin_unlock(&block_group->tree_lock);
@@ -2173,7 +2174,6 @@ void btrfs_init_free_cluster(struct btrfs_free_cluster *cluster)
 	spin_lock_init(&cluster->refill_lock);
 	cluster->root = RB_ROOT;
 	cluster->max_size = 0;
-	cluster->points_to_bitmap = false;
 	INIT_LIST_HEAD(&cluster->block_group_list);
 	cluster->block_group = NULL;
 }