1 files changed, 375 insertions, 155 deletions

diff --git a/fs/btrfs/free-space-cache.c b/fs/btrfs/free-space-cache.c
index d1e5f0e84c5..768b9523662 100644
--- a/fs/btrfs/free-space-cache.c
+++ b/fs/btrfs/free-space-cache.c
@@ -18,6 +18,15 @@
 
 #include <linux/sched.h>
 #include "ctree.h"
+#include "free-space-cache.h"
+#include "transaction.h"
+
+struct btrfs_free_space {
+	struct rb_node bytes_index;
+	struct rb_node offset_index;
+	u64 offset;
+	u64 bytes;
+};
 
 static int tree_insert_offset(struct rb_root *root, u64 offset,
 			      struct rb_node *node)
@@ -68,14 +77,24 @@ static int tree_insert_bytes(struct rb_root *root, u64 bytes,
 }
 
 /*
- * searches the tree for the given offset.  If contains is set we will return
- * the free space that contains the given offset.  If contains is not set we
- * will return the free space that starts at or after the given offset and is
- * at least bytes long.
+ * searches the tree for the given offset.
+ *
+ * fuzzy == 1: this is used for allocations where we are given a hint of where
+ * to look for free space.  Because the hint may not be completely on an offset
+ * mark, or the hint may no longer point to free space we need to fudge our
+ * results a bit.  So we look for free space starting at or after offset with at
+ * least bytes size.  We prefer to find as close to the given offset as we can.
+ * Also if the offset is within a free space range, then we will return the free
+ * space that contains the given offset, which means we can return a free space
+ * chunk with an offset before the provided offset.
+ *
+ * fuzzy == 0: this is just a normal tree search.  Give us the free space that
+ * starts at the given offset which is at least bytes size, and if its not there
+ * return NULL.
  */
 static struct btrfs_free_space *tree_search_offset(struct rb_root *root,
 						   u64 offset, u64 bytes,
-						   int contains)
+						   int fuzzy)
 {
 	struct rb_node *n = root->rb_node;
 	struct btrfs_free_space *entry, *ret = NULL;
@@ -84,13 +103,14 @@ static struct btrfs_free_space *tree_search_offset(struct rb_root *root,
 		entry = rb_entry(n, struct btrfs_free_space, offset_index);
 
 		if (offset < entry->offset) {
-			if (!contains &&
+			if (fuzzy &&
 			    (!ret || entry->offset < ret->offset) &&
 			    (bytes <= entry->bytes))
 				ret = entry;
 			n = n->rb_left;
 		} else if (offset > entry->offset) {
-			if ((entry->offset + entry->bytes - 1) >= offset &&
+			if (fuzzy &&
+			    (entry->offset + entry->bytes - 1) >= offset &&
 			    bytes <= entry->bytes) {
 				ret = entry;
 				break;
@@ -171,6 +191,7 @@ static int link_free_space(struct btrfs_block_group_cache *block_group,
 	int ret = 0;
 
 
+	BUG_ON(!info->bytes);
 	ret = tree_insert_offset(&block_group->free_space_offset, info->offset,
 				 &info->offset_index);
 	if (ret)
@@ -184,108 +205,70 @@ static int link_free_space(struct btrfs_block_group_cache *block_group,
 	return ret;
 }
 
-static int __btrfs_add_free_space(struct btrfs_block_group_cache *block_group,
-				  u64 offset, u64 bytes)
+int btrfs_add_free_space(struct btrfs_block_group_cache *block_group,
+			 u64 offset, u64 bytes)
 {
 	struct btrfs_free_space *right_info;
 	struct btrfs_free_space *left_info;
 	struct btrfs_free_space *info = NULL;
-	struct btrfs_free_space *alloc_info;
 	int ret = 0;
 
-	alloc_info = kzalloc(sizeof(struct btrfs_free_space), GFP_NOFS);
-	if (!alloc_info)
+	info = kzalloc(sizeof(struct btrfs_free_space), GFP_NOFS);
+	if (!info)
 		return -ENOMEM;
 
+	info->offset = offset;
+	info->bytes = bytes;
+
+	spin_lock(&block_group->tree_lock);
+
 	/*
 	 * first we want to see if there is free space adjacent to the range we
 	 * are adding, if there is remove that struct and add a new one to
 	 * cover the entire range
 	 */
 	right_info = tree_search_offset(&block_group->free_space_offset,
-					offset+bytes, 0, 1);
+					offset+bytes, 0, 0);
 	left_info = tree_search_offset(&block_group->free_space_offset,
 				       offset-1, 0, 1);
 
-	if (right_info && right_info->offset == offset+bytes) {
+	if (right_info) {
 		unlink_free_space(block_group, right_info);
-		info = right_info;
-		info->offset = offset;
-		info->bytes += bytes;
-	} else if (right_info && right_info->offset != offset+bytes) {
-		printk(KERN_ERR "btrfs adding space in the middle of an "
-		       "existing free space area. existing: "
-		       "offset=%llu, bytes=%llu. new: offset=%llu, "
-		       "bytes=%llu\n", (unsigned long long)right_info->offset,
-		       (unsigned long long)right_info->bytes,
-		       (unsigned long long)offset,
-		       (unsigned long long)bytes);
-		BUG();
+		info->bytes += right_info->bytes;
+		kfree(right_info);
 	}
 
-	if (left_info) {
+	if (left_info && left_info->offset + left_info->bytes == offset) {
 		unlink_free_space(block_group, left_info);
-
-		if (unlikely((left_info->offset + left_info->bytes) !=
-			     offset)) {
-			printk(KERN_ERR "btrfs free space to the left "
-			       "of new free space isn't "
-			       "quite right. existing: offset=%llu, "
-			       "bytes=%llu. new: offset=%llu, bytes=%llu\n",
-			       (unsigned long long)left_info->offset,
-			       (unsigned long long)left_info->bytes,
-			       (unsigned long long)offset,
-			       (unsigned long long)bytes);
-			BUG();
-		}
-
-		if (info) {
-			info->offset = left_info->offset;
-			info->bytes += left_info->bytes;
-			kfree(left_info);
-		} else {
-			info = left_info;
-			info->bytes += bytes;
-		}
+		info->offset = left_info->offset;
+		info->bytes += left_info->bytes;
+		kfree(left_info);
 	}
 
-	if (info) {
-		ret = link_free_space(block_group, info);
-		if (!ret)
-			info = NULL;
-		goto out;
-	}
-
-	info = alloc_info;
-	alloc_info = NULL;
-	info->offset = offset;
-	info->bytes = bytes;
-
 	ret = link_free_space(block_group, info);
 	if (ret)
 		kfree(info);
-out:
+
+	spin_unlock(&block_group->tree_lock);
+
 	if (ret) {
 		printk(KERN_ERR "btrfs: unable to add free space :%d\n", ret);
-		if (ret == -EEXIST)
-			BUG();
+		BUG_ON(ret == -EEXIST);
 	}
 
-	kfree(alloc_info);
-
 	return ret;
 }
 
-static int
-__btrfs_remove_free_space(struct btrfs_block_group_cache *block_group,
-			  u64 offset, u64 bytes)
+int btrfs_remove_free_space(struct btrfs_block_group_cache *block_group,
+			    u64 offset, u64 bytes)
 {
 	struct btrfs_free_space *info;
 	int ret = 0;
 
+	spin_lock(&block_group->tree_lock);
+
 	info = tree_search_offset(&block_group->free_space_offset, offset, 0,
 				  1);
-
 	if (info && info->offset == offset) {
 		if (info->bytes < bytes) {
 			printk(KERN_ERR "Found free space at %llu, size %llu,"
@@ -295,12 +278,14 @@ __btrfs_remove_free_space(struct btrfs_block_group_cache *block_group,
 			       (unsigned long long)bytes);
 			WARN_ON(1);
 			ret = -EINVAL;
+			spin_unlock(&block_group->tree_lock);
 			goto out;
 		}
 		unlink_free_space(block_group, info);
 
 		if (info->bytes == bytes) {
 			kfree(info);
+			spin_unlock(&block_group->tree_lock);
 			goto out;
 		}
 
@@ -308,6 +293,7 @@ __btrfs_remove_free_space(struct btrfs_block_group_cache *block_group,
 		info->bytes -= bytes;
 
 		ret = link_free_space(block_group, info);
+		spin_unlock(&block_group->tree_lock);
 		BUG_ON(ret);
 	} else if (info && info->offset < offset &&
 		   info->offset + info->bytes >= offset + bytes) {
@@ -333,70 +319,33 @@ __btrfs_remove_free_space(struct btrfs_block_group_cache *block_group,
 			 */
 			kfree(info);
 		}
-
+		spin_unlock(&block_group->tree_lock);
 		/* step two, insert a new info struct to cover anything
 		 * before the hole
 		 */
-		ret = __btrfs_add_free_space(block_group, old_start,
-					     offset - old_start);
+		ret = btrfs_add_free_space(block_group, old_start,
+					   offset - old_start);
 		BUG_ON(ret);
 	} else {
+		spin_unlock(&block_group->tree_lock);
+		if (!info) {
+			printk(KERN_ERR "couldn't find space %llu to free\n",
+			       (unsigned long long)offset);
+			printk(KERN_ERR "cached is %d, offset %llu bytes %llu\n",
+			       block_group->cached, block_group->key.objectid,
+			       block_group->key.offset);
+			btrfs_dump_free_space(block_group, bytes);
+		} else if (info) {
+			printk(KERN_ERR "hmm, found offset=%llu bytes=%llu, "
+			       "but wanted offset=%llu bytes=%llu\n",
+			       info->offset, info->bytes, offset, bytes);
+		}
 		WARN_ON(1);
 	}
 out:
 	return ret;
 }
 
-int btrfs_add_free_space(struct btrfs_block_group_cache *block_group,
-			 u64 offset, u64 bytes)
-{
-	int ret;
-	struct btrfs_free_space *sp;
-
-	mutex_lock(&block_group->alloc_mutex);
-	ret = __btrfs_add_free_space(block_group, offset, bytes);
-	sp = tree_search_offset(&block_group->free_space_offset, offset, 0, 1);
-	BUG_ON(!sp);
-	mutex_unlock(&block_group->alloc_mutex);
-
-	return ret;
-}
-
-int btrfs_add_free_space_lock(struct btrfs_block_group_cache *block_group,
-			      u64 offset, u64 bytes)
-{
-	int ret;
-	struct btrfs_free_space *sp;
-
-	ret = __btrfs_add_free_space(block_group, offset, bytes);
-	sp = tree_search_offset(&block_group->free_space_offset, offset, 0, 1);
-	BUG_ON(!sp);
-
-	return ret;
-}
-
-int btrfs_remove_free_space(struct btrfs_block_group_cache *block_group,
-			    u64 offset, u64 bytes)
-{
-	int ret = 0;
-
-	mutex_lock(&block_group->alloc_mutex);
-	ret = __btrfs_remove_free_space(block_group, offset, bytes);
-	mutex_unlock(&block_group->alloc_mutex);
-
-	return ret;
-}
-
-int btrfs_remove_free_space_lock(struct btrfs_block_group_cache *block_group,
-				 u64 offset, u64 bytes)
-{
-	int ret;
-
-	ret = __btrfs_remove_free_space(block_group, offset, bytes);
-
-	return ret;
-}
-
 void btrfs_dump_free_space(struct btrfs_block_group_cache *block_group,
 			   u64 bytes)
 {
@@ -408,6 +357,8 @@ void btrfs_dump_free_space(struct btrfs_block_group_cache *block_group,
 		info = rb_entry(n, struct btrfs_free_space, offset_index);
 		if (info->bytes >= bytes)
 			count++;
+		printk(KERN_ERR "entry offset %llu, bytes %llu\n", info->offset,
+		       info->bytes);
 	}
 	printk(KERN_INFO "%d blocks of free space at or bigger than bytes is"
 	       "\n", count);
@@ -428,68 +379,337 @@ u64 btrfs_block_group_free_space(struct btrfs_block_group_cache *block_group)
 	return ret;
 }
 
+/*
+ * for a given cluster, put all of its extents back into the free
+ * space cache.  If the block group passed doesn't match the block group
+ * pointed to by the cluster, someone else raced in and freed the
+ * cluster already.  In that case, we just return without changing anything
+ */
+static int
+__btrfs_return_cluster_to_free_space(
+			     struct btrfs_block_group_cache *block_group,
+			     struct btrfs_free_cluster *cluster)
+{
+	struct btrfs_free_space *entry;
+	struct rb_node *node;
+
+	spin_lock(&cluster->lock);
+	if (cluster->block_group != block_group)
+		goto out;
+
+	cluster->window_start = 0;
+	node = rb_first(&cluster->root);
+	while(node) {
+		entry = rb_entry(node, struct btrfs_free_space, offset_index);
+		node = rb_next(&entry->offset_index);
+		rb_erase(&entry->offset_index, &cluster->root);
+		link_free_space(block_group, entry);
+	}
+	list_del_init(&cluster->block_group_list);
+
+	btrfs_put_block_group(cluster->block_group);
+	cluster->block_group = NULL;
+	cluster->root.rb_node = NULL;
+out:
+	spin_unlock(&cluster->lock);
+	return 0;
+}
+
 void btrfs_remove_free_space_cache(struct btrfs_block_group_cache *block_group)
 {
 	struct btrfs_free_space *info;
 	struct rb_node *node;
+	struct btrfs_free_cluster *cluster;
+	struct btrfs_free_cluster *safe;
+
+	spin_lock(&block_group->tree_lock);
+
+	list_for_each_entry_safe(cluster, safe, &block_group->cluster_list,
+				 block_group_list) {
+
+		WARN_ON(cluster->block_group != block_group);
+		__btrfs_return_cluster_to_free_space(block_group, cluster);
+	}
 
-	mutex_lock(&block_group->alloc_mutex);
 	while ((node = rb_last(&block_group->free_space_bytes)) != NULL) {
 		info = rb_entry(node, struct btrfs_free_space, bytes_index);
 		unlink_free_space(block_group, info);
 		kfree(info);
 		if (need_resched()) {
-			mutex_unlock(&block_group->alloc_mutex);
+			spin_unlock(&block_group->tree_lock);
 			cond_resched();
-			mutex_lock(&block_group->alloc_mutex);
+			spin_lock(&block_group->tree_lock);
 		}
 	}
-	mutex_unlock(&block_group->alloc_mutex);
+	spin_unlock(&block_group->tree_lock);
 }
 
-#if 0
-static struct btrfs_free_space *btrfs_find_free_space_offset(struct
-						      btrfs_block_group_cache
-						      *block_group, u64 offset,
-						      u64 bytes)
+u64 btrfs_find_space_for_alloc(struct btrfs_block_group_cache *block_group,
+			       u64 offset, u64 bytes, u64 empty_size)
 {
-	struct btrfs_free_space *ret;
+	struct btrfs_free_space *entry = NULL;
+	u64 ret = 0;
 
-	mutex_lock(&block_group->alloc_mutex);
-	ret = tree_search_offset(&block_group->free_space_offset, offset,
-				 bytes, 0);
-	mutex_unlock(&block_group->alloc_mutex);
+	spin_lock(&block_group->tree_lock);
+	entry = tree_search_offset(&block_group->free_space_offset, offset,
+				   bytes + empty_size, 1);
+	if (!entry)
+		entry = tree_search_bytes(&block_group->free_space_bytes,
+					  offset, bytes + empty_size);
+	if (entry) {
+		unlink_free_space(block_group, entry);
+		ret = entry->offset;
+		entry->offset += bytes;
+		entry->bytes -= bytes;
+
+		if (!entry->bytes)
+			kfree(entry);
+		else
+			link_free_space(block_group, entry);
+	}
+	spin_unlock(&block_group->tree_lock);
 
 	return ret;
 }
 
-static struct btrfs_free_space *btrfs_find_free_space_bytes(struct
-						     btrfs_block_group_cache
-						     *block_group, u64 offset,
-						     u64 bytes)
+/*
+ * given a cluster, put all of its extents back into the free space
+ * cache.  If a block group is passed, this function will only free
+ * a cluster that belongs to the passed block group.
+ *
+ * Otherwise, it'll get a reference on the block group pointed to by the
+ * cluster and remove the cluster from it.
+ */
+int btrfs_return_cluster_to_free_space(
+			       struct btrfs_block_group_cache *block_group,
+			       struct btrfs_free_cluster *cluster)
 {
-	struct btrfs_free_space *ret;
+	int ret;
 
-	mutex_lock(&block_group->alloc_mutex);
+	/* first, get a safe pointer to the block group */
+	spin_lock(&cluster->lock);
+	if (!block_group) {
+		block_group = cluster->block_group;
+		if (!block_group) {
+			spin_unlock(&cluster->lock);
+			return 0;
+		}
+	} else if (cluster->block_group != block_group) {
+		/* someone else has already freed it don't redo their work */
+		spin_unlock(&cluster->lock);
+		return 0;
+	}
+	atomic_inc(&block_group->count);
+	spin_unlock(&cluster->lock);
 
-	ret = tree_search_bytes(&block_group->free_space_bytes, offset, bytes);
-	mutex_unlock(&block_group->alloc_mutex);
+	/* now return any extents the cluster had on it */
+	spin_lock(&block_group->tree_lock);
+	ret = __btrfs_return_cluster_to_free_space(block_group, cluster);
+	spin_unlock(&block_group->tree_lock);
 
+	/* finally drop our ref */
+	btrfs_put_block_group(block_group);
 	return ret;
 }
-#endif
 
-struct btrfs_free_space *btrfs_find_free_space(struct btrfs_block_group_cache
-					       *block_group, u64 offset,
-					       u64 bytes)
+/*
+ * given a cluster, try to allocate 'bytes' from it, returns 0
+ * if it couldn't find anything suitably large, or a logical disk offset
+ * if things worked out
+ */
+u64 btrfs_alloc_from_cluster(struct btrfs_block_group_cache *block_group,
+			     struct btrfs_free_cluster *cluster, u64 bytes,
+			     u64 min_start)
+{
+	struct btrfs_free_space *entry = NULL;
+	struct rb_node *node;
+	u64 ret = 0;
+
+	spin_lock(&cluster->lock);
+	if (bytes > cluster->max_size)
+		goto out;
+
+	if (cluster->block_group != block_group)
+		goto out;
+
+	node = rb_first(&cluster->root);
+	if (!node)
+		goto out;
+
+	entry = rb_entry(node, struct btrfs_free_space, offset_index);
+
+	while(1) {
+		if (entry->bytes < bytes || entry->offset < min_start) {
+			struct rb_node *node;
+
+			node = rb_next(&entry->offset_index);
+			if (!node)
+				break;
+			entry = rb_entry(node, struct btrfs_free_space,
+					 offset_index);
+			continue;
+		}
+		ret = entry->offset;
+
+		entry->offset += bytes;
+		entry->bytes -= bytes;
+
+		if (entry->bytes == 0) {
+			rb_erase(&entry->offset_index, &cluster->root);
+			kfree(entry);
+		}
+		break;
+	}
+out:
+	spin_unlock(&cluster->lock);
+	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.
+ *
+ * returns zero and sets up cluster if things worked out, otherwise
+ * it returns -enospc
+ */
+int btrfs_find_space_cluster(struct btrfs_trans_handle *trans,
+			     struct btrfs_block_group_cache *block_group,
+			     struct btrfs_free_cluster *cluster,
+			     u64 offset, u64 bytes, u64 empty_size)
 {
-	struct btrfs_free_space *ret = NULL;
+	struct btrfs_free_space *entry = NULL;
+	struct rb_node *node;
+	struct btrfs_free_space *next;
+	struct btrfs_free_space *last;
+	u64 min_bytes;
+	u64 window_start;
+	u64 window_free;
+	u64 max_extent = 0;
+	int total_retries = 0;
+	int ret;
+
+	/* for metadata, allow allocates with more holes */
+	if (block_group->flags & BTRFS_BLOCK_GROUP_METADATA) {
+		/*
+		 * we want to do larger allocations when we are
+		 * flushing out the delayed refs, it helps prevent
+		 * making more work as we go along.
+		 */
+		if (trans->transaction->delayed_refs.flushing)
+			min_bytes = max(bytes, (bytes + empty_size) >> 1);
+		else
+			min_bytes = max(bytes, (bytes + empty_size) >> 4);
+	} else
+		min_bytes = max(bytes, (bytes + empty_size) >> 2);
+
+	spin_lock(&block_group->tree_lock);
+	spin_lock(&cluster->lock);
+
+	/* someone already found a cluster, hooray */
+	if (cluster->block_group) {
+		ret = 0;
+		goto out;
+	}
+again:
+	min_bytes = min(min_bytes, bytes + empty_size);
+	entry = tree_search_bytes(&block_group->free_space_bytes,
+				  offset, min_bytes);
+	if (!entry) {
+		ret = -ENOSPC;
+		goto out;
+	}
+	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 >= bytes + empty_size)
+			break;
 
-	ret = tree_search_offset(&block_group->free_space_offset, offset,
-				 bytes, 0);
-	if (!ret)
-		ret = tree_search_bytes(&block_group->free_space_bytes,
-					offset, bytes);
+		node = rb_next(&last->offset_index);
+		if (!node) {
+			ret = -ENOSPC;
+			goto out;
+		}
+		next = rb_entry(node, struct btrfs_free_space, offset_index);
+
+		/*
+		 * we haven't filled the empty size and the window is
+		 * very large.  reset and try again
+		 */
+		if (next->offset - window_start > (bytes + empty_size) * 2) {
+			entry = next;
+			window_start = entry->offset;
+			window_free = entry->bytes;
+			last = entry;
+			max_extent = 0;
+			total_retries++;
+			if (total_retries % 256 == 0) {
+				if (min_bytes >= (bytes + empty_size)) {
+					ret = -ENOSPC;
+					goto out;
+				}
+				/*
+				 * grow our allocation a bit, we're not having
+				 * much luck
+				 */
+				min_bytes *= 2;
+				goto again;
+			}
+		} 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);
+		unlink_free_space(block_group, entry);
+		ret = tree_insert_offset(&cluster->root, entry->offset,
+					 &entry->offset_index);
+		BUG_ON(ret);
+
+		if (!node || entry == last)
+			break;
+
+		entry = rb_entry(node, struct btrfs_free_space, offset_index);
+	}
+	ret = 0;
+	cluster->max_size = max_extent;
+	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);
 
 	return ret;
 }
+
+/*
+ * simple code to zero out a cluster
+ */
+void btrfs_init_free_cluster(struct btrfs_free_cluster *cluster)
+{
+	spin_lock_init(&cluster->lock);
+	spin_lock_init(&cluster->refill_lock);
+	cluster->root.rb_node = NULL;
+	cluster->max_size = 0;
+	INIT_LIST_HEAD(&cluster->block_group_list);
+	cluster->block_group = NULL;
+}
+