1 files changed, 403 insertions, 297 deletions

diff --git a/fs/btrfs/delayed-ref.c b/fs/btrfs/delayed-ref.c
index 6f2e48d697dd..cab94d141f66 100644
--- a/fs/btrfs/delayed-ref.c
+++ b/fs/btrfs/delayed-ref.c
@@ -16,8 +16,7 @@
 #include "fs.h"
 
 struct kmem_cache *btrfs_delayed_ref_head_cachep;
-struct kmem_cache *btrfs_delayed_tree_ref_cachep;
-struct kmem_cache *btrfs_delayed_data_ref_cachep;
+struct kmem_cache *btrfs_delayed_ref_node_cachep;
 struct kmem_cache *btrfs_delayed_extent_op_cachep;
 /*
  * delayed back reference update tracking.  For subvolume trees
@@ -57,16 +56,20 @@ bool btrfs_check_space_for_delayed_refs(struct btrfs_fs_info *fs_info)
  * Release a ref head's reservation.
  *
  * @fs_info:  the filesystem
- * @nr:       number of items to drop
+ * @nr_refs:  number of delayed refs to drop
+ * @nr_csums: number of csum items to drop
  *
  * Drops the delayed ref head's count from the delayed refs rsv and free any
  * excess reservation we had.
  */
-void btrfs_delayed_refs_rsv_release(struct btrfs_fs_info *fs_info, int nr)
+void btrfs_delayed_refs_rsv_release(struct btrfs_fs_info *fs_info, int nr_refs, int nr_csums)
 {
 	struct btrfs_block_rsv *block_rsv = &fs_info->delayed_refs_rsv;
-	const u64 num_bytes = btrfs_calc_delayed_ref_bytes(fs_info, nr);
-	u64 released = 0;
+	u64 num_bytes;
+	u64 released;
+
+	num_bytes = btrfs_calc_delayed_ref_bytes(fs_info, nr_refs);
+	num_bytes += btrfs_calc_delayed_ref_csum_bytes(fs_info, nr_csums);
 
 	released = btrfs_block_rsv_release(fs_info, block_rsv, num_bytes, NULL);
 	if (released)
@@ -77,68 +80,118 @@ void btrfs_delayed_refs_rsv_release(struct btrfs_fs_info *fs_info, int nr)
 /*
  * Adjust the size of the delayed refs rsv.
  *
- * This is to be called anytime we may have adjusted trans->delayed_ref_updates,
- * it'll calculate the additional size and add it to the delayed_refs_rsv.
+ * This is to be called anytime we may have adjusted trans->delayed_ref_updates
+ * or trans->delayed_ref_csum_deletions, it'll calculate the additional size and
+ * add it to the delayed_refs_rsv.
  */
 void btrfs_update_delayed_refs_rsv(struct btrfs_trans_handle *trans)
 {
 	struct btrfs_fs_info *fs_info = trans->fs_info;
 	struct btrfs_block_rsv *delayed_rsv = &fs_info->delayed_refs_rsv;
+	struct btrfs_block_rsv *local_rsv = &trans->delayed_rsv;
 	u64 num_bytes;
+	u64 reserved_bytes;
 
-	if (!trans->delayed_ref_updates)
+	num_bytes = btrfs_calc_delayed_ref_bytes(fs_info, trans->delayed_ref_updates);
+	num_bytes += btrfs_calc_delayed_ref_csum_bytes(fs_info,
+						       trans->delayed_ref_csum_deletions);
+
+	if (num_bytes == 0)
 		return;
 
-	num_bytes = btrfs_calc_delayed_ref_bytes(fs_info,
-						 trans->delayed_ref_updates);
+	/*
+	 * Try to take num_bytes from the transaction's local delayed reserve.
+	 * If not possible, try to take as much as it's available. If the local
+	 * reserve doesn't have enough reserved space, the delayed refs reserve
+	 * will be refilled next time btrfs_delayed_refs_rsv_refill() is called
+	 * by someone or if a transaction commit is triggered before that, the
+	 * global block reserve will be used. We want to minimize using the
+	 * global block reserve for cases we can account for in advance, to
+	 * avoid exhausting it and reach -ENOSPC during a transaction commit.
+	 */
+	spin_lock(&local_rsv->lock);
+	reserved_bytes = min(num_bytes, local_rsv->reserved);
+	local_rsv->reserved -= reserved_bytes;
+	local_rsv->full = (local_rsv->reserved >= local_rsv->size);
+	spin_unlock(&local_rsv->lock);
 
 	spin_lock(&delayed_rsv->lock);
 	delayed_rsv->size += num_bytes;
-	delayed_rsv->full = false;
+	delayed_rsv->reserved += reserved_bytes;
+	delayed_rsv->full = (delayed_rsv->reserved >= delayed_rsv->size);
 	spin_unlock(&delayed_rsv->lock);
 	trans->delayed_ref_updates = 0;
+	trans->delayed_ref_csum_deletions = 0;
 }
 
 /*
- * Transfer bytes to our delayed refs rsv.
- *
- * @fs_info:   the filesystem
- * @num_bytes: number of bytes to transfer
- *
- * This transfers up to the num_bytes amount, previously reserved, to the
- * delayed_refs_rsv.  Any extra bytes are returned to the space info.
+ * Adjust the size of the delayed refs block reserve for 1 block group item
+ * insertion, used after allocating a block group.
  */
-void btrfs_migrate_to_delayed_refs_rsv(struct btrfs_fs_info *fs_info,
-				       u64 num_bytes)
+void btrfs_inc_delayed_refs_rsv_bg_inserts(struct btrfs_fs_info *fs_info)
 {
-	struct btrfs_block_rsv *delayed_refs_rsv = &fs_info->delayed_refs_rsv;
-	u64 to_free = 0;
+	struct btrfs_block_rsv *delayed_rsv = &fs_info->delayed_refs_rsv;
 
-	spin_lock(&delayed_refs_rsv->lock);
-	if (delayed_refs_rsv->size > delayed_refs_rsv->reserved) {
-		u64 delta = delayed_refs_rsv->size -
-			delayed_refs_rsv->reserved;
-		if (num_bytes > delta) {
-			to_free = num_bytes - delta;
-			num_bytes = delta;
-		}
-	} else {
-		to_free = num_bytes;
-		num_bytes = 0;
-	}
+	spin_lock(&delayed_rsv->lock);
+	/*
+	 * Inserting a block group item does not require changing the free space
+	 * tree, only the extent tree or the block group tree, so this is all we
+	 * need.
+	 */
+	delayed_rsv->size += btrfs_calc_insert_metadata_size(fs_info, 1);
+	delayed_rsv->full = false;
+	spin_unlock(&delayed_rsv->lock);
+}
 
-	if (num_bytes)
-		delayed_refs_rsv->reserved += num_bytes;
-	if (delayed_refs_rsv->reserved >= delayed_refs_rsv->size)
-		delayed_refs_rsv->full = true;
-	spin_unlock(&delayed_refs_rsv->lock);
+/*
+ * Adjust the size of the delayed refs block reserve to release space for 1
+ * block group item insertion.
+ */
+void btrfs_dec_delayed_refs_rsv_bg_inserts(struct btrfs_fs_info *fs_info)
+{
+	struct btrfs_block_rsv *delayed_rsv = &fs_info->delayed_refs_rsv;
+	const u64 num_bytes = btrfs_calc_insert_metadata_size(fs_info, 1);
+	u64 released;
+
+	released = btrfs_block_rsv_release(fs_info, delayed_rsv, num_bytes, NULL);
+	if (released > 0)
+		trace_btrfs_space_reservation(fs_info, "delayed_refs_rsv",
+					      0, released, 0);
+}
+
+/*
+ * Adjust the size of the delayed refs block reserve for 1 block group item
+ * update.
+ */
+void btrfs_inc_delayed_refs_rsv_bg_updates(struct btrfs_fs_info *fs_info)
+{
+	struct btrfs_block_rsv *delayed_rsv = &fs_info->delayed_refs_rsv;
+
+	spin_lock(&delayed_rsv->lock);
+	/*
+	 * Updating a block group item does not result in new nodes/leaves and
+	 * does not require changing the free space tree, only the extent tree
+	 * or the block group tree, so this is all we need.
+	 */
+	delayed_rsv->size += btrfs_calc_metadata_size(fs_info, 1);
+	delayed_rsv->full = false;
+	spin_unlock(&delayed_rsv->lock);
+}
 
-	if (num_bytes)
+/*
+ * Adjust the size of the delayed refs block reserve to release space for 1
+ * block group item update.
+ */
+void btrfs_dec_delayed_refs_rsv_bg_updates(struct btrfs_fs_info *fs_info)
+{
+	struct btrfs_block_rsv *delayed_rsv = &fs_info->delayed_refs_rsv;
+	const u64 num_bytes = btrfs_calc_metadata_size(fs_info, 1);
+	u64 released;
+
+	released = btrfs_block_rsv_release(fs_info, delayed_rsv, num_bytes, NULL);
+	if (released > 0)
 		trace_btrfs_space_reservation(fs_info, "delayed_refs_rsv",
-					      0, num_bytes, 1);
-	if (to_free)
-		btrfs_space_info_free_bytes_may_use(fs_info,
-				delayed_refs_rsv->space_info, to_free);
+					      0, released, 0);
 }
 
 /*
@@ -154,6 +207,7 @@ int btrfs_delayed_refs_rsv_refill(struct btrfs_fs_info *fs_info,
 				  enum btrfs_reserve_flush_enum flush)
 {
 	struct btrfs_block_rsv *block_rsv = &fs_info->delayed_refs_rsv;
+	struct btrfs_space_info *space_info = block_rsv->space_info;
 	u64 limit = btrfs_calc_delayed_ref_bytes(fs_info, 1);
 	u64 num_bytes = 0;
 	u64 refilled_bytes;
@@ -170,7 +224,7 @@ int btrfs_delayed_refs_rsv_refill(struct btrfs_fs_info *fs_info,
 	if (!num_bytes)
 		return 0;
 
-	ret = btrfs_reserve_metadata_bytes(fs_info, block_rsv, num_bytes, flush);
+	ret = btrfs_reserve_metadata_bytes(fs_info, space_info, num_bytes, flush);
 	if (ret)
 		return ret;
 
@@ -199,8 +253,7 @@ int btrfs_delayed_refs_rsv_refill(struct btrfs_fs_info *fs_info,
 	spin_unlock(&block_rsv->lock);
 
 	if (to_free > 0)
-		btrfs_space_info_free_bytes_may_use(fs_info, block_rsv->space_info,
-						    to_free);
+		btrfs_space_info_free_bytes_may_use(fs_info, space_info, to_free);
 
 	if (refilled_bytes > 0)
 		trace_btrfs_space_reservation(fs_info, "delayed_refs_rsv", 0,
@@ -209,50 +262,19 @@ int btrfs_delayed_refs_rsv_refill(struct btrfs_fs_info *fs_info,
 }
 
 /*
- * compare two delayed tree backrefs with same bytenr and type
- */
-static int comp_tree_refs(struct btrfs_delayed_tree_ref *ref1,
-			  struct btrfs_delayed_tree_ref *ref2)
-{
-	if (ref1->node.type == BTRFS_TREE_BLOCK_REF_KEY) {
-		if (ref1->root < ref2->root)
-			return -1;
-		if (ref1->root > ref2->root)
-			return 1;
-	} else {
-		if (ref1->parent < ref2->parent)
-			return -1;
-		if (ref1->parent > ref2->parent)
-			return 1;
-	}
-	return 0;
-}
-
-/*
  * compare two delayed data backrefs with same bytenr and type
  */
-static int comp_data_refs(struct btrfs_delayed_data_ref *ref1,
-			  struct btrfs_delayed_data_ref *ref2)
+static int comp_data_refs(struct btrfs_delayed_ref_node *ref1,
+			  struct btrfs_delayed_ref_node *ref2)
 {
-	if (ref1->node.type == BTRFS_EXTENT_DATA_REF_KEY) {
-		if (ref1->root < ref2->root)
-			return -1;
-		if (ref1->root > ref2->root)
-			return 1;
-		if (ref1->objectid < ref2->objectid)
-			return -1;
-		if (ref1->objectid > ref2->objectid)
-			return 1;
-		if (ref1->offset < ref2->offset)
-			return -1;
-		if (ref1->offset > ref2->offset)
-			return 1;
-	} else {
-		if (ref1->parent < ref2->parent)
-			return -1;
-		if (ref1->parent > ref2->parent)
-			return 1;
-	}
+	if (ref1->data_ref.objectid < ref2->data_ref.objectid)
+		return -1;
+	if (ref1->data_ref.objectid > ref2->data_ref.objectid)
+		return 1;
+	if (ref1->data_ref.offset < ref2->data_ref.offset)
+		return -1;
+	if (ref1->data_ref.offset > ref2->data_ref.offset)
+		return 1;
 	return 0;
 }
 
@@ -266,13 +288,20 @@ static int comp_refs(struct btrfs_delayed_ref_node *ref1,
 		return -1;
 	if (ref1->type > ref2->type)
 		return 1;
-	if (ref1->type == BTRFS_TREE_BLOCK_REF_KEY ||
-	    ref1->type == BTRFS_SHARED_BLOCK_REF_KEY)
-		ret = comp_tree_refs(btrfs_delayed_node_to_tree_ref(ref1),
-				     btrfs_delayed_node_to_tree_ref(ref2));
-	else
-		ret = comp_data_refs(btrfs_delayed_node_to_data_ref(ref1),
-				     btrfs_delayed_node_to_data_ref(ref2));
+	if (ref1->type == BTRFS_SHARED_BLOCK_REF_KEY ||
+	    ref1->type == BTRFS_SHARED_DATA_REF_KEY) {
+		if (ref1->parent < ref2->parent)
+			return -1;
+		if (ref1->parent > ref2->parent)
+			return 1;
+	} else {
+		if (ref1->ref_root < ref2->ref_root)
+			return -1;
+		if (ref1->ref_root > ref2->ref_root)
+			return 1;
+		if (ref1->type == BTRFS_EXTENT_DATA_REF_KEY)
+			ret = comp_data_refs(ref1, ref2);
+	}
 	if (ret)
 		return ret;
 	if (check_seq) {
@@ -422,7 +451,8 @@ int btrfs_delayed_ref_lock(struct btrfs_delayed_ref_root *delayed_refs,
 	return 0;
 }
 
-static inline void drop_delayed_ref(struct btrfs_delayed_ref_root *delayed_refs,
+static inline void drop_delayed_ref(struct btrfs_fs_info *fs_info,
+				    struct btrfs_delayed_ref_root *delayed_refs,
 				    struct btrfs_delayed_ref_head *head,
 				    struct btrfs_delayed_ref_node *ref)
 {
@@ -433,9 +463,11 @@ static inline void drop_delayed_ref(struct btrfs_delayed_ref_root *delayed_refs,
 		list_del(&ref->add_list);
 	btrfs_put_delayed_ref(ref);
 	atomic_dec(&delayed_refs->num_entries);
+	btrfs_delayed_refs_rsv_release(fs_info, 1, 0);
 }
 
-static bool merge_ref(struct btrfs_delayed_ref_root *delayed_refs,
+static bool merge_ref(struct btrfs_fs_info *fs_info,
+		      struct btrfs_delayed_ref_root *delayed_refs,
 		      struct btrfs_delayed_ref_head *head,
 		      struct btrfs_delayed_ref_node *ref,
 		      u64 seq)
@@ -464,10 +496,10 @@ static bool merge_ref(struct btrfs_delayed_ref_root *delayed_refs,
 			mod = -next->ref_mod;
 		}
 
-		drop_delayed_ref(delayed_refs, head, next);
+		drop_delayed_ref(fs_info, delayed_refs, head, next);
 		ref->ref_mod += mod;
 		if (ref->ref_mod == 0) {
-			drop_delayed_ref(delayed_refs, head, ref);
+			drop_delayed_ref(fs_info, delayed_refs, head, ref);
 			done = true;
 		} else {
 			/*
@@ -505,7 +537,7 @@ again:
 		ref = rb_entry(node, struct btrfs_delayed_ref_node, ref_node);
 		if (seq && ref->seq >= seq)
 			continue;
-		if (merge_ref(delayed_refs, head, ref, seq))
+		if (merge_ref(fs_info, delayed_refs, head, ref, seq))
 			goto again;
 	}
 }
@@ -584,10 +616,11 @@ void btrfs_delete_ref_head(struct btrfs_delayed_ref_root *delayed_refs,
  * Return true if the ref was merged into an existing one (and therefore can be
  * freed by the caller).
  */
-static bool insert_delayed_ref(struct btrfs_delayed_ref_root *root,
+static bool insert_delayed_ref(struct btrfs_trans_handle *trans,
 			       struct btrfs_delayed_ref_head *href,
 			       struct btrfs_delayed_ref_node *ref)
 {
+	struct btrfs_delayed_ref_root *root = &trans->transaction->delayed_refs;
 	struct btrfs_delayed_ref_node *exist;
 	int mod;
 
@@ -598,6 +631,7 @@ static bool insert_delayed_ref(struct btrfs_delayed_ref_root *root,
 			list_add_tail(&ref->add_list, &href->ref_add_list);
 		atomic_inc(&root->num_entries);
 		spin_unlock(&href->lock);
+		trans->delayed_ref_updates++;
 		return false;
 	}
 
@@ -626,7 +660,7 @@ static bool insert_delayed_ref(struct btrfs_delayed_ref_root *root,
 
 	/* remove existing tail if its ref_mod is zero */
 	if (exist->ref_mod == 0)
-		drop_delayed_ref(root, href, exist);
+		drop_delayed_ref(trans->fs_info, root, href, exist);
 	spin_unlock(&href->lock);
 	return true;
 }
@@ -647,6 +681,15 @@ static noinline void update_existing_head_ref(struct btrfs_trans_handle *trans,
 	BUG_ON(existing->is_data != update->is_data);
 
 	spin_lock(&existing->lock);
+
+	/*
+	 * When freeing an extent, we may not know the owning root when we
+	 * first create the head_ref. However, some deref before the last deref
+	 * will know it, so we just need to update the head_ref accordingly.
+	 */
+	if (!existing->owning_root)
+		existing->owning_root = update->owning_root;
+
 	if (update->must_insert_reserved) {
 		/* if the extent was freed and then
 		 * reallocated before the delayed ref
@@ -656,6 +699,7 @@ static noinline void update_existing_head_ref(struct btrfs_trans_handle *trans,
 		 * Set it again here
 		 */
 		existing->must_insert_reserved = update->must_insert_reserved;
+		existing->owning_root = update->owning_root;
 
 		/*
 		 * update the num_bytes so we make sure the accounting
@@ -695,6 +739,8 @@ static noinline void update_existing_head_ref(struct btrfs_trans_handle *trans,
 	/*
 	 * If we are going to from a positive ref mod to a negative or vice
 	 * versa we need to make sure to adjust pending_csums accordingly.
+	 * We reserve bytes for csum deletion when adding or updating a ref head
+	 * see add_delayed_ref_head() for more details.
 	 */
 	if (existing->is_data) {
 		u64 csum_leaves =
@@ -703,11 +749,11 @@ static noinline void update_existing_head_ref(struct btrfs_trans_handle *trans,
 
 		if (existing->total_ref_mod >= 0 && old_ref_mod < 0) {
 			delayed_refs->pending_csums -= existing->num_bytes;
-			btrfs_delayed_refs_rsv_release(fs_info, csum_leaves);
+			btrfs_delayed_refs_rsv_release(fs_info, 0, csum_leaves);
 		}
 		if (existing->total_ref_mod < 0 && old_ref_mod >= 0) {
 			delayed_refs->pending_csums += existing->num_bytes;
-			trans->delayed_ref_updates += csum_leaves;
+			trans->delayed_ref_csum_deletions += csum_leaves;
 		}
 	}
 
@@ -715,18 +761,20 @@ static noinline void update_existing_head_ref(struct btrfs_trans_handle *trans,
 }
 
 static void init_delayed_ref_head(struct btrfs_delayed_ref_head *head_ref,
+				  struct btrfs_ref *generic_ref,
 				  struct btrfs_qgroup_extent_record *qrecord,
-				  u64 bytenr, u64 num_bytes, u64 ref_root,
-				  u64 reserved, int action, bool is_data,
-				  bool is_system)
+				  u64 reserved)
 {
 	int count_mod = 1;
 	bool must_insert_reserved = false;
 
 	/* If reserved is provided, it must be a data extent. */
-	BUG_ON(!is_data && reserved);
+	BUG_ON(generic_ref->type != BTRFS_REF_DATA && reserved);
 
-	switch (action) {
+	switch (generic_ref->action) {
+	case BTRFS_ADD_DELAYED_REF:
+		/* count_mod is already set to 1. */
+		break;
 	case BTRFS_UPDATE_DELAYED_HEAD:
 		count_mod = 0;
 		break;
@@ -755,12 +803,14 @@ static void init_delayed_ref_head(struct btrfs_delayed_ref_head *head_ref,
 	}
 
 	refcount_set(&head_ref->refs, 1);
-	head_ref->bytenr = bytenr;
-	head_ref->num_bytes = num_bytes;
+	head_ref->bytenr = generic_ref->bytenr;
+	head_ref->num_bytes = generic_ref->num_bytes;
 	head_ref->ref_mod = count_mod;
+	head_ref->reserved_bytes = reserved;
 	head_ref->must_insert_reserved = must_insert_reserved;
-	head_ref->is_data = is_data;
-	head_ref->is_system = is_system;
+	head_ref->owning_root = generic_ref->owning_root;
+	head_ref->is_data = (generic_ref->type == BTRFS_REF_DATA);
+	head_ref->is_system = (generic_ref->ref_root == BTRFS_CHUNK_TREE_OBJECTID);
 	head_ref->ref_tree = RB_ROOT_CACHED;
 	INIT_LIST_HEAD(&head_ref->ref_add_list);
 	RB_CLEAR_NODE(&head_ref->href_node);
@@ -769,13 +819,19 @@ static void init_delayed_ref_head(struct btrfs_delayed_ref_head *head_ref,
 	spin_lock_init(&head_ref->lock);
 	mutex_init(&head_ref->mutex);
 
+	/* If not metadata set an impossible level to help debugging. */
+	if (generic_ref->type == BTRFS_REF_METADATA)
+		head_ref->level = generic_ref->tree_ref.level;
+	else
+		head_ref->level = U8_MAX;
+
 	if (qrecord) {
-		if (ref_root && reserved) {
+		if (generic_ref->ref_root && reserved) {
 			qrecord->data_rsv = reserved;
-			qrecord->data_rsv_refroot = ref_root;
+			qrecord->data_rsv_refroot = generic_ref->ref_root;
 		}
-		qrecord->bytenr = bytenr;
-		qrecord->num_bytes = num_bytes;
+		qrecord->bytenr = generic_ref->bytenr;
+		qrecord->num_bytes = generic_ref->num_bytes;
 		qrecord->old_roots = NULL;
 	}
 }
@@ -784,6 +840,8 @@ static void init_delayed_ref_head(struct btrfs_delayed_ref_head *head_ref,
  * helper function to actually insert a head node into the rbtree.
  * this does all the dirty work in terms of maintaining the correct
  * overall modification count.
+ *
+ * Returns an error pointer in case of an error.
  */
 static noinline struct btrfs_delayed_ref_head *
 add_delayed_ref_head(struct btrfs_trans_handle *trans,
@@ -791,6 +849,7 @@ add_delayed_ref_head(struct btrfs_trans_handle *trans,
 		     struct btrfs_qgroup_extent_record *qrecord,
 		     int action, bool *qrecord_inserted_ret)
 {
+	struct btrfs_fs_info *fs_info = trans->fs_info;
 	struct btrfs_delayed_ref_head *existing;
 	struct btrfs_delayed_ref_root *delayed_refs;
 	bool qrecord_inserted = false;
@@ -799,14 +858,23 @@ add_delayed_ref_head(struct btrfs_trans_handle *trans,
 
 	/* Record qgroup extent info if provided */
 	if (qrecord) {
-		if (btrfs_qgroup_trace_extent_nolock(trans->fs_info,
-					delayed_refs, qrecord))
+		int ret;
+
+		ret = btrfs_qgroup_trace_extent_nolock(fs_info, delayed_refs, qrecord);
+		if (ret) {
+			/* Clean up if insertion fails or item exists. */
+			xa_release(&delayed_refs->dirty_extents,
+				   qrecord->bytenr >> fs_info->sectorsize_bits);
+			/* Caller responsible for freeing qrecord on error. */
+			if (ret < 0)
+				return ERR_PTR(ret);
 			kfree(qrecord);
-		else
+		} else {
 			qrecord_inserted = true;
+		}
 	}
 
-	trace_add_delayed_ref_head(trans->fs_info, head_ref, action);
+	trace_add_delayed_ref_head(fs_info, head_ref, action);
 
 	existing = htree_insert(&delayed_refs->href_root,
 				&head_ref->href_node);
@@ -819,16 +887,20 @@ add_delayed_ref_head(struct btrfs_trans_handle *trans,
 		kmem_cache_free(btrfs_delayed_ref_head_cachep, head_ref);
 		head_ref = existing;
 	} else {
+		/*
+		 * We reserve the amount of bytes needed to delete csums when
+		 * adding the ref head and not when adding individual drop refs
+		 * since the csum items are deleted only after running the last
+		 * delayed drop ref (the data extent's ref count drops to 0).
+		 */
 		if (head_ref->is_data && head_ref->ref_mod < 0) {
 			delayed_refs->pending_csums += head_ref->num_bytes;
-			trans->delayed_ref_updates +=
-				btrfs_csum_bytes_to_leaves(trans->fs_info,
-							   head_ref->num_bytes);
+			trans->delayed_ref_csum_deletions +=
+				btrfs_csum_bytes_to_leaves(fs_info, head_ref->num_bytes);
 		}
 		delayed_refs->num_heads++;
 		delayed_refs->num_heads_ready++;
 		atomic_inc(&delayed_refs->num_entries);
-		trans->delayed_ref_updates++;
 	}
 	if (qrecord_inserted_ret)
 		*qrecord_inserted_ret = qrecord_inserted;
@@ -837,8 +909,7 @@ add_delayed_ref_head(struct btrfs_trans_handle *trans,
 }
 
 /*
- * init_delayed_ref_common - Initialize the structure which represents a
- *			     modification to a an extent.
+ * Initialize the structure which represents a modification to a an extent.
  *
  * @fs_info:    Internal to the mounted filesystem mount structure.
  *
@@ -863,90 +934,111 @@ add_delayed_ref_head(struct btrfs_trans_handle *trans,
  */
 static void init_delayed_ref_common(struct btrfs_fs_info *fs_info,
 				    struct btrfs_delayed_ref_node *ref,
-				    u64 bytenr, u64 num_bytes, u64 ref_root,
-				    int action, u8 ref_type)
+				    struct btrfs_ref *generic_ref)
 {
+	int action = generic_ref->action;
 	u64 seq = 0;
 
 	if (action == BTRFS_ADD_DELAYED_EXTENT)
 		action = BTRFS_ADD_DELAYED_REF;
 
-	if (is_fstree(ref_root))
+	if (is_fstree(generic_ref->ref_root))
 		seq = atomic64_read(&fs_info->tree_mod_seq);
 
 	refcount_set(&ref->refs, 1);
-	ref->bytenr = bytenr;
-	ref->num_bytes = num_bytes;
+	ref->bytenr = generic_ref->bytenr;
+	ref->num_bytes = generic_ref->num_bytes;
 	ref->ref_mod = 1;
 	ref->action = action;
 	ref->seq = seq;
-	ref->type = ref_type;
+	ref->type = btrfs_ref_type(generic_ref);
+	ref->ref_root = generic_ref->ref_root;
+	ref->parent = generic_ref->parent;
 	RB_CLEAR_NODE(&ref->ref_node);
 	INIT_LIST_HEAD(&ref->add_list);
+
+	if (generic_ref->type == BTRFS_REF_DATA)
+		ref->data_ref = generic_ref->data_ref;
+	else
+		ref->tree_ref = generic_ref->tree_ref;
 }
 
-/*
- * add a delayed tree ref.  This does all of the accounting required
- * to make sure the delayed ref is eventually processed before this
- * transaction commits.
- */
-int btrfs_add_delayed_tree_ref(struct btrfs_trans_handle *trans,
-			       struct btrfs_ref *generic_ref,
-			       struct btrfs_delayed_extent_op *extent_op)
+void btrfs_init_tree_ref(struct btrfs_ref *generic_ref, int level, u64 mod_root,
+			 bool skip_qgroup)
+{
+#ifdef CONFIG_BTRFS_FS_REF_VERIFY
+	/* If @real_root not set, use @root as fallback */
+	generic_ref->real_root = mod_root ?: generic_ref->ref_root;
+#endif
+	generic_ref->tree_ref.level = level;
+	generic_ref->type = BTRFS_REF_METADATA;
+	if (skip_qgroup || !(is_fstree(generic_ref->ref_root) &&
+			     (!mod_root || is_fstree(mod_root))))
+		generic_ref->skip_qgroup = true;
+	else
+		generic_ref->skip_qgroup = false;
+
+}
+
+void btrfs_init_data_ref(struct btrfs_ref *generic_ref, u64 ino, u64 offset,
+			 u64 mod_root, bool skip_qgroup)
+{
+#ifdef CONFIG_BTRFS_FS_REF_VERIFY
+	/* If @real_root not set, use @root as fallback */
+	generic_ref->real_root = mod_root ?: generic_ref->ref_root;
+#endif
+	generic_ref->data_ref.objectid = ino;
+	generic_ref->data_ref.offset = offset;
+	generic_ref->type = BTRFS_REF_DATA;
+	if (skip_qgroup || !(is_fstree(generic_ref->ref_root) &&
+			     (!mod_root || is_fstree(mod_root))))
+		generic_ref->skip_qgroup = true;
+	else
+		generic_ref->skip_qgroup = false;
+}
+
+static int add_delayed_ref(struct btrfs_trans_handle *trans,
+			   struct btrfs_ref *generic_ref,
+			   struct btrfs_delayed_extent_op *extent_op,
+			   u64 reserved)
 {
 	struct btrfs_fs_info *fs_info = trans->fs_info;
-	struct btrfs_delayed_tree_ref *ref;
+	struct btrfs_delayed_ref_node *node;
 	struct btrfs_delayed_ref_head *head_ref;
+	struct btrfs_delayed_ref_head *new_head_ref;
 	struct btrfs_delayed_ref_root *delayed_refs;
 	struct btrfs_qgroup_extent_record *record = NULL;
 	bool qrecord_inserted;
-	bool is_system;
-	bool merged;
 	int action = generic_ref->action;
-	int level = generic_ref->tree_ref.level;
-	u64 bytenr = generic_ref->bytenr;
-	u64 num_bytes = generic_ref->len;
-	u64 parent = generic_ref->parent;
-	u8 ref_type;
-
-	is_system = (generic_ref->tree_ref.owning_root == BTRFS_CHUNK_TREE_OBJECTID);
+	bool merged;
+	int ret;
 
-	ASSERT(generic_ref->type == BTRFS_REF_METADATA && generic_ref->action);
-	ref = kmem_cache_alloc(btrfs_delayed_tree_ref_cachep, GFP_NOFS);
-	if (!ref)
+	node = kmem_cache_alloc(btrfs_delayed_ref_node_cachep, GFP_NOFS);
+	if (!node)
 		return -ENOMEM;
 
 	head_ref = kmem_cache_alloc(btrfs_delayed_ref_head_cachep, GFP_NOFS);
 	if (!head_ref) {
-		kmem_cache_free(btrfs_delayed_tree_ref_cachep, ref);
-		return -ENOMEM;
+		ret = -ENOMEM;
+		goto free_node;
 	}
 
-	if (test_bit(BTRFS_FS_QUOTA_ENABLED, &fs_info->flags) &&
-	    !generic_ref->skip_qgroup) {
+	if (btrfs_qgroup_full_accounting(fs_info) && !generic_ref->skip_qgroup) {
 		record = kzalloc(sizeof(*record), GFP_NOFS);
 		if (!record) {
-			kmem_cache_free(btrfs_delayed_tree_ref_cachep, ref);
-			kmem_cache_free(btrfs_delayed_ref_head_cachep, head_ref);
-			return -ENOMEM;
+			ret = -ENOMEM;
+			goto free_head_ref;
+		}
+		if (xa_reserve(&trans->transaction->delayed_refs.dirty_extents,
+			       generic_ref->bytenr >> fs_info->sectorsize_bits,
+			       GFP_NOFS)) {
+			ret = -ENOMEM;
+			goto free_record;
 		}
 	}
 
-	if (parent)
-		ref_type = BTRFS_SHARED_BLOCK_REF_KEY;
-	else
-		ref_type = BTRFS_TREE_BLOCK_REF_KEY;
-
-	init_delayed_ref_common(fs_info, &ref->node, bytenr, num_bytes,
-				generic_ref->tree_ref.owning_root, action,
-				ref_type);
-	ref->root = generic_ref->tree_ref.owning_root;
-	ref->parent = parent;
-	ref->level = level;
-
-	init_delayed_ref_head(head_ref, record, bytenr, num_bytes,
-			      generic_ref->tree_ref.owning_root, 0, action,
-			      false, is_system);
+	init_delayed_ref_common(fs_info, node, generic_ref);
+	init_delayed_ref_head(head_ref, generic_ref, record, reserved);
 	head_ref->extent_op = extent_op;
 
 	delayed_refs = &trans->transaction->delayed_refs;
@@ -956,10 +1048,16 @@ int btrfs_add_delayed_tree_ref(struct btrfs_trans_handle *trans,
 	 * insert both the head node and the new ref without dropping
 	 * the spin lock
 	 */
-	head_ref = add_delayed_ref_head(trans, head_ref, record,
-					action, &qrecord_inserted);
+	new_head_ref = add_delayed_ref_head(trans, head_ref, record,
+					    action, &qrecord_inserted);
+	if (IS_ERR(new_head_ref)) {
+		spin_unlock(&delayed_refs->lock);
+		ret = PTR_ERR(new_head_ref);
+		goto free_record;
+	}
+	head_ref = new_head_ref;
 
-	merged = insert_delayed_ref(delayed_refs, head_ref, &ref->node);
+	merged = insert_delayed_ref(trans, head_ref, node);
 	spin_unlock(&delayed_refs->lock);
 
 	/*
@@ -968,16 +1066,36 @@ int btrfs_add_delayed_tree_ref(struct btrfs_trans_handle *trans,
 	 */
 	btrfs_update_delayed_refs_rsv(trans);
 
-	trace_add_delayed_tree_ref(fs_info, &ref->node, ref,
-				   action == BTRFS_ADD_DELAYED_EXTENT ?
-				   BTRFS_ADD_DELAYED_REF : action);
+	if (generic_ref->type == BTRFS_REF_DATA)
+		trace_add_delayed_data_ref(trans->fs_info, node);
+	else
+		trace_add_delayed_tree_ref(trans->fs_info, node);
 	if (merged)
-		kmem_cache_free(btrfs_delayed_tree_ref_cachep, ref);
+		kmem_cache_free(btrfs_delayed_ref_node_cachep, node);
 
 	if (qrecord_inserted)
-		btrfs_qgroup_trace_extent_post(trans, record);
-
+		return btrfs_qgroup_trace_extent_post(trans, record);
 	return 0;
+
+free_record:
+	kfree(record);
+free_head_ref:
+	kmem_cache_free(btrfs_delayed_ref_head_cachep, head_ref);
+free_node:
+	kmem_cache_free(btrfs_delayed_ref_node_cachep, node);
+	return ret;
+}
+
+/*
+ * Add a delayed tree ref. This does all of the accounting required to make sure
+ * the delayed ref is eventually processed before this transaction commits.
+ */
+int btrfs_add_delayed_tree_ref(struct btrfs_trans_handle *trans,
+			       struct btrfs_ref *generic_ref,
+			       struct btrfs_delayed_extent_op *extent_op)
+{
+	ASSERT(generic_ref->type == BTRFS_REF_METADATA && generic_ref->action);
+	return add_delayed_ref(trans, generic_ref, extent_op, 0);
 }
 
 /*
@@ -987,114 +1105,44 @@ int btrfs_add_delayed_data_ref(struct btrfs_trans_handle *trans,
 			       struct btrfs_ref *generic_ref,
 			       u64 reserved)
 {
-	struct btrfs_fs_info *fs_info = trans->fs_info;
-	struct btrfs_delayed_data_ref *ref;
-	struct btrfs_delayed_ref_head *head_ref;
-	struct btrfs_delayed_ref_root *delayed_refs;
-	struct btrfs_qgroup_extent_record *record = NULL;
-	bool qrecord_inserted;
-	int action = generic_ref->action;
-	bool merged;
-	u64 bytenr = generic_ref->bytenr;
-	u64 num_bytes = generic_ref->len;
-	u64 parent = generic_ref->parent;
-	u64 ref_root = generic_ref->data_ref.owning_root;
-	u64 owner = generic_ref->data_ref.ino;
-	u64 offset = generic_ref->data_ref.offset;
-	u8 ref_type;
-
-	ASSERT(generic_ref->type == BTRFS_REF_DATA && action);
-	ref = kmem_cache_alloc(btrfs_delayed_data_ref_cachep, GFP_NOFS);
-	if (!ref)
-		return -ENOMEM;
-
-	if (parent)
-	        ref_type = BTRFS_SHARED_DATA_REF_KEY;
-	else
-	        ref_type = BTRFS_EXTENT_DATA_REF_KEY;
-	init_delayed_ref_common(fs_info, &ref->node, bytenr, num_bytes,
-				ref_root, action, ref_type);
-	ref->root = ref_root;
-	ref->parent = parent;
-	ref->objectid = owner;
-	ref->offset = offset;
-
-
-	head_ref = kmem_cache_alloc(btrfs_delayed_ref_head_cachep, GFP_NOFS);
-	if (!head_ref) {
-		kmem_cache_free(btrfs_delayed_data_ref_cachep, ref);
-		return -ENOMEM;
-	}
-
-	if (test_bit(BTRFS_FS_QUOTA_ENABLED, &fs_info->flags) &&
-	    !generic_ref->skip_qgroup) {
-		record = kzalloc(sizeof(*record), GFP_NOFS);
-		if (!record) {
-			kmem_cache_free(btrfs_delayed_data_ref_cachep, ref);
-			kmem_cache_free(btrfs_delayed_ref_head_cachep,
-					head_ref);
-			return -ENOMEM;
-		}
-	}
-
-	init_delayed_ref_head(head_ref, record, bytenr, num_bytes, ref_root,
-			      reserved, action, true, false);
-	head_ref->extent_op = NULL;
-
-	delayed_refs = &trans->transaction->delayed_refs;
-	spin_lock(&delayed_refs->lock);
-
-	/*
-	 * insert both the head node and the new ref without dropping
-	 * the spin lock
-	 */
-	head_ref = add_delayed_ref_head(trans, head_ref, record,
-					action, &qrecord_inserted);
-
-	merged = insert_delayed_ref(delayed_refs, head_ref, &ref->node);
-	spin_unlock(&delayed_refs->lock);
-
-	/*
-	 * Need to update the delayed_refs_rsv with any changes we may have
-	 * made.
-	 */
-	btrfs_update_delayed_refs_rsv(trans);
-
-	trace_add_delayed_data_ref(trans->fs_info, &ref->node, ref,
-				   action == BTRFS_ADD_DELAYED_EXTENT ?
-				   BTRFS_ADD_DELAYED_REF : action);
-	if (merged)
-		kmem_cache_free(btrfs_delayed_data_ref_cachep, ref);
-
-
-	if (qrecord_inserted)
-		return btrfs_qgroup_trace_extent_post(trans, record);
-	return 0;
+	ASSERT(generic_ref->type == BTRFS_REF_DATA && generic_ref->action);
+	return add_delayed_ref(trans, generic_ref, NULL, reserved);
 }
 
 int btrfs_add_delayed_extent_op(struct btrfs_trans_handle *trans,
-				u64 bytenr, u64 num_bytes,
+				u64 bytenr, u64 num_bytes, u8 level,
 				struct btrfs_delayed_extent_op *extent_op)
 {
 	struct btrfs_delayed_ref_head *head_ref;
+	struct btrfs_delayed_ref_head *head_ref_ret;
 	struct btrfs_delayed_ref_root *delayed_refs;
+	struct btrfs_ref generic_ref = {
+		.type = BTRFS_REF_METADATA,
+		.action = BTRFS_UPDATE_DELAYED_HEAD,
+		.bytenr = bytenr,
+		.num_bytes = num_bytes,
+		.tree_ref.level = level,
+	};
 
 	head_ref = kmem_cache_alloc(btrfs_delayed_ref_head_cachep, GFP_NOFS);
 	if (!head_ref)
 		return -ENOMEM;
 
-	init_delayed_ref_head(head_ref, NULL, bytenr, num_bytes, 0, 0,
-			      BTRFS_UPDATE_DELAYED_HEAD, false, false);
+	init_delayed_ref_head(head_ref, &generic_ref, NULL, 0);
 	head_ref->extent_op = extent_op;
 
 	delayed_refs = &trans->transaction->delayed_refs;
 	spin_lock(&delayed_refs->lock);
 
-	add_delayed_ref_head(trans, head_ref, NULL, BTRFS_UPDATE_DELAYED_HEAD,
-			     NULL);
-
+	head_ref_ret = add_delayed_ref_head(trans, head_ref, NULL,
+					    BTRFS_UPDATE_DELAYED_HEAD, NULL);
 	spin_unlock(&delayed_refs->lock);
 
+	if (IS_ERR(head_ref_ret)) {
+		kmem_cache_free(btrfs_delayed_ref_head_cachep, head_ref);
+		return PTR_ERR(head_ref_ret);
+	}
+
 	/*
 	 * Need to update the delayed_refs_rsv with any changes we may have
 	 * made.
@@ -1103,6 +1151,14 @@ int btrfs_add_delayed_extent_op(struct btrfs_trans_handle *trans,
 	return 0;
 }
 
+void btrfs_put_delayed_ref(struct btrfs_delayed_ref_node *ref)
+{
+	if (refcount_dec_and_test(&ref->refs)) {
+		WARN_ON(!RB_EMPTY_NODE(&ref->ref_node));
+		kmem_cache_free(btrfs_delayed_ref_node_cachep, ref);
+	}
+}
+
 /*
  * This does a simple search for the head node for a given extent.  Returns the
  * head node if found, or NULL if not.
@@ -1115,41 +1171,91 @@ btrfs_find_delayed_ref_head(struct btrfs_delayed_ref_root *delayed_refs, u64 byt
 	return find_ref_head(delayed_refs, bytenr, false);
 }
 
+static int find_comp(struct btrfs_delayed_ref_node *entry, u64 root, u64 parent)
+{
+	int type = parent ? BTRFS_SHARED_BLOCK_REF_KEY : BTRFS_TREE_BLOCK_REF_KEY;
+
+	if (type < entry->type)
+		return -1;
+	if (type > entry->type)
+		return 1;
+
+	if (type == BTRFS_TREE_BLOCK_REF_KEY) {
+		if (root < entry->ref_root)
+			return -1;
+		if (root > entry->ref_root)
+			return 1;
+	} else {
+		if (parent < entry->parent)
+			return -1;
+		if (parent > entry->parent)
+			return 1;
+	}
+	return 0;
+}
+
+/*
+ * Check to see if a given root/parent reference is attached to the head.  This
+ * only checks for BTRFS_ADD_DELAYED_REF references that match, as that
+ * indicates the reference exists for the given root or parent.  This is for
+ * tree blocks only.
+ *
+ * @head: the head of the bytenr we're searching.
+ * @root: the root objectid of the reference if it is a normal reference.
+ * @parent: the parent if this is a shared backref.
+ */
+bool btrfs_find_delayed_tree_ref(struct btrfs_delayed_ref_head *head,
+				 u64 root, u64 parent)
+{
+	struct rb_node *node;
+	bool found = false;
+
+	lockdep_assert_held(&head->mutex);
+
+	spin_lock(&head->lock);
+	node = head->ref_tree.rb_root.rb_node;
+	while (node) {
+		struct btrfs_delayed_ref_node *entry;
+		int ret;
+
+		entry = rb_entry(node, struct btrfs_delayed_ref_node, ref_node);
+		ret = find_comp(entry, root, parent);
+		if (ret < 0) {
+			node = node->rb_left;
+		} else if (ret > 0) {
+			node = node->rb_right;
+		} else {
+			/*
+			 * We only want to count ADD actions, as drops mean the
+			 * ref doesn't exist.
+			 */
+			if (entry->action == BTRFS_ADD_DELAYED_REF)
+				found = true;
+			break;
+		}
+	}
+	spin_unlock(&head->lock);
+	return found;
+}
+
 void __cold btrfs_delayed_ref_exit(void)
 {
 	kmem_cache_destroy(btrfs_delayed_ref_head_cachep);
-	kmem_cache_destroy(btrfs_delayed_tree_ref_cachep);
-	kmem_cache_destroy(btrfs_delayed_data_ref_cachep);
+	kmem_cache_destroy(btrfs_delayed_ref_node_cachep);
 	kmem_cache_destroy(btrfs_delayed_extent_op_cachep);
 }
 
 int __init btrfs_delayed_ref_init(void)
 {
-	btrfs_delayed_ref_head_cachep = kmem_cache_create(
-				"btrfs_delayed_ref_head",
-				sizeof(struct btrfs_delayed_ref_head), 0,
-				SLAB_MEM_SPREAD, NULL);
+	btrfs_delayed_ref_head_cachep = KMEM_CACHE(btrfs_delayed_ref_head, 0);
 	if (!btrfs_delayed_ref_head_cachep)
 		goto fail;
 
-	btrfs_delayed_tree_ref_cachep = kmem_cache_create(
-				"btrfs_delayed_tree_ref",
-				sizeof(struct btrfs_delayed_tree_ref), 0,
-				SLAB_MEM_SPREAD, NULL);
-	if (!btrfs_delayed_tree_ref_cachep)
-		goto fail;
-
-	btrfs_delayed_data_ref_cachep = kmem_cache_create(
-				"btrfs_delayed_data_ref",
-				sizeof(struct btrfs_delayed_data_ref), 0,
-				SLAB_MEM_SPREAD, NULL);
-	if (!btrfs_delayed_data_ref_cachep)
+	btrfs_delayed_ref_node_cachep = KMEM_CACHE(btrfs_delayed_ref_node, 0);
+	if (!btrfs_delayed_ref_node_cachep)
 		goto fail;
 
-	btrfs_delayed_extent_op_cachep = kmem_cache_create(
-				"btrfs_delayed_extent_op",
-				sizeof(struct btrfs_delayed_extent_op), 0,
-				SLAB_MEM_SPREAD, NULL);
+	btrfs_delayed_extent_op_cachep = KMEM_CACHE(btrfs_delayed_extent_op, 0);
 	if (!btrfs_delayed_extent_op_cachep)
 		goto fail;