Merge branch 'misc-6.14' into next-fixes
diff --git a/fs/btrfs/Makefile b/fs/btrfs/Makefile
index 3cfc440..2d5f048 100644
--- a/fs/btrfs/Makefile
+++ b/fs/btrfs/Makefile
@@ -44,4 +44,4 @@
 	tests/extent-buffer-tests.o tests/btrfs-tests.o \
 	tests/extent-io-tests.o tests/inode-tests.o tests/qgroup-tests.o \
 	tests/free-space-tree-tests.o tests/extent-map-tests.o \
-	tests/raid-stripe-tree-tests.o
+	tests/raid-stripe-tree-tests.o tests/delayed-refs-tests.o
diff --git a/fs/btrfs/async-thread.c b/fs/btrfs/async-thread.c
index 361a866..a4c51600 100644
--- a/fs/btrfs/async-thread.c
+++ b/fs/btrfs/async-thread.c
@@ -18,7 +18,7 @@ enum {
 };
 
 #define NO_THRESHOLD (-1)
-#define DFT_THRESHOLD (32)
+#define DEFAULT_THRESHOLD (32)
 
 struct btrfs_workqueue {
 	struct workqueue_struct *normal_wq;
@@ -94,9 +94,9 @@ struct btrfs_workqueue *btrfs_alloc_workqueue(struct btrfs_fs_info *fs_info,
 
 	ret->limit_active = limit_active;
 	if (thresh == 0)
-		thresh = DFT_THRESHOLD;
+		thresh = DEFAULT_THRESHOLD;
 	/* For low threshold, disabling threshold is a better choice */
-	if (thresh < DFT_THRESHOLD) {
+	if (thresh < DEFAULT_THRESHOLD) {
 		ret->current_active = limit_active;
 		ret->thresh = NO_THRESHOLD;
 	} else {
diff --git a/fs/btrfs/backref.c b/fs/btrfs/backref.c
index 04f53ca..3d3923c 100644
--- a/fs/btrfs/backref.c
+++ b/fs/btrfs/backref.c
@@ -250,6 +250,21 @@ static int prelim_ref_compare(const struct prelim_ref *ref1,
 	return 0;
 }
 
+static int prelim_ref_rb_add_cmp(const struct rb_node *new,
+				 const struct rb_node *exist)
+{
+	const struct prelim_ref *ref_new =
+		rb_entry(new, struct prelim_ref, rbnode);
+	const struct prelim_ref *ref_exist =
+		rb_entry(exist, struct prelim_ref, rbnode);
+
+	/*
+	 * prelim_ref_compare() expects the first parameter as the existing one,
+	 * different from the rb_find_add_cached() order.
+	 */
+	return prelim_ref_compare(ref_exist, ref_new);
+}
+
 static void update_share_count(struct share_check *sc, int oldcount,
 			       int newcount, const struct prelim_ref *newref)
 {
@@ -278,55 +293,39 @@ static void prelim_ref_insert(const struct btrfs_fs_info *fs_info,
 			      struct share_check *sc)
 {
 	struct rb_root_cached *root;
-	struct rb_node **p;
-	struct rb_node *parent = NULL;
-	struct prelim_ref *ref;
-	int result;
-	bool leftmost = true;
+	struct rb_node *exist;
 
 	root = &preftree->root;
-	p = &root->rb_root.rb_node;
+	exist = rb_find_add_cached(&newref->rbnode, root, prelim_ref_rb_add_cmp);
+	if (exist) {
+		struct prelim_ref *ref = rb_entry(exist, struct prelim_ref, rbnode);
+		/* Identical refs, merge them and free @newref */
+		struct extent_inode_elem *eie = ref->inode_list;
 
-	while (*p) {
-		parent = *p;
-		ref = rb_entry(parent, struct prelim_ref, rbnode);
-		result = prelim_ref_compare(ref, newref);
-		if (result < 0) {
-			p = &(*p)->rb_left;
-		} else if (result > 0) {
-			p = &(*p)->rb_right;
-			leftmost = false;
-		} else {
-			/* Identical refs, merge them and free @newref */
-			struct extent_inode_elem *eie = ref->inode_list;
+		while (eie && eie->next)
+			eie = eie->next;
 
-			while (eie && eie->next)
-				eie = eie->next;
-
-			if (!eie)
-				ref->inode_list = newref->inode_list;
-			else
-				eie->next = newref->inode_list;
-			trace_btrfs_prelim_ref_merge(fs_info, ref, newref,
-						     preftree->count);
-			/*
-			 * A delayed ref can have newref->count < 0.
-			 * The ref->count is updated to follow any
-			 * BTRFS_[ADD|DROP]_DELAYED_REF actions.
-			 */
-			update_share_count(sc, ref->count,
-					   ref->count + newref->count, newref);
-			ref->count += newref->count;
-			free_pref(newref);
-			return;
-		}
+		if (!eie)
+			ref->inode_list = newref->inode_list;
+		else
+			eie->next = newref->inode_list;
+		trace_btrfs_prelim_ref_merge(fs_info, ref, newref,
+							preftree->count);
+		/*
+		 * A delayed ref can have newref->count < 0.
+		 * The ref->count is updated to follow any
+		 * BTRFS_[ADD|DROP]_DELAYED_REF actions.
+		 */
+		update_share_count(sc, ref->count,
+					ref->count + newref->count, newref);
+		ref->count += newref->count;
+		free_pref(newref);
+		return;
 	}
 
 	update_share_count(sc, 0, newref->count, newref);
 	preftree->count++;
 	trace_btrfs_prelim_ref_insert(fs_info, newref, NULL, preftree->count);
-	rb_link_node(&newref->rbnode, parent, p);
-	rb_insert_color_cached(&newref->rbnode, root, leftmost);
 }
 
 /*
@@ -3022,9 +3021,6 @@ void btrfs_backref_init_cache(struct btrfs_fs_info *fs_info,
 	cache->rb_root = RB_ROOT;
 	for (i = 0; i < BTRFS_MAX_LEVEL; i++)
 		INIT_LIST_HEAD(&cache->pending[i]);
-	INIT_LIST_HEAD(&cache->changed);
-	INIT_LIST_HEAD(&cache->detached);
-	INIT_LIST_HEAD(&cache->leaves);
 	INIT_LIST_HEAD(&cache->pending_edge);
 	INIT_LIST_HEAD(&cache->useless_node);
 	cache->fs_info = fs_info;
@@ -3132,29 +3128,17 @@ void btrfs_backref_drop_node(struct btrfs_backref_cache *tree,
 void btrfs_backref_cleanup_node(struct btrfs_backref_cache *cache,
 				struct btrfs_backref_node *node)
 {
-	struct btrfs_backref_node *upper;
 	struct btrfs_backref_edge *edge;
 
 	if (!node)
 		return;
 
-	BUG_ON(!node->lowest && !node->detached);
 	while (!list_empty(&node->upper)) {
 		edge = list_entry(node->upper.next, struct btrfs_backref_edge,
 				  list[LOWER]);
-		upper = edge->node[UPPER];
 		list_del(&edge->list[LOWER]);
 		list_del(&edge->list[UPPER]);
 		btrfs_backref_free_edge(cache, edge);
-
-		/*
-		 * Add the node to leaf node list if no other child block
-		 * cached.
-		 */
-		if (list_empty(&upper->lower)) {
-			list_add_tail(&upper->lower, &cache->leaves);
-			upper->lowest = 1;
-		}
 	}
 
 	btrfs_backref_drop_node(cache, node);
@@ -3166,33 +3150,13 @@ void btrfs_backref_cleanup_node(struct btrfs_backref_cache *cache,
 void btrfs_backref_release_cache(struct btrfs_backref_cache *cache)
 {
 	struct btrfs_backref_node *node;
-	int i;
 
-	while (!list_empty(&cache->detached)) {
-		node = list_entry(cache->detached.next,
-				  struct btrfs_backref_node, list);
+	while ((node = rb_entry_safe(rb_first(&cache->rb_root),
+				     struct btrfs_backref_node, rb_node)))
 		btrfs_backref_cleanup_node(cache, node);
-	}
 
-	while (!list_empty(&cache->leaves)) {
-		node = list_entry(cache->leaves.next,
-				  struct btrfs_backref_node, lower);
-		btrfs_backref_cleanup_node(cache, node);
-	}
-
-	for (i = 0; i < BTRFS_MAX_LEVEL; i++) {
-		while (!list_empty(&cache->pending[i])) {
-			node = list_first_entry(&cache->pending[i],
-						struct btrfs_backref_node,
-						list);
-			btrfs_backref_cleanup_node(cache, node);
-		}
-	}
 	ASSERT(list_empty(&cache->pending_edge));
 	ASSERT(list_empty(&cache->useless_node));
-	ASSERT(list_empty(&cache->changed));
-	ASSERT(list_empty(&cache->detached));
-	ASSERT(RB_EMPTY_ROOT(&cache->rb_root));
 	ASSERT(!cache->nr_nodes);
 	ASSERT(!cache->nr_edges);
 }
@@ -3316,8 +3280,12 @@ static int handle_indirect_tree_backref(struct btrfs_trans_handle *trans,
 	root = btrfs_get_fs_root(fs_info, ref_key->offset, false);
 	if (IS_ERR(root))
 		return PTR_ERR(root);
-	if (!test_bit(BTRFS_ROOT_SHAREABLE, &root->state))
-		cur->cowonly = 1;
+
+	/* We shouldn't be using backref cache for non-shareable roots. */
+	if (unlikely(!test_bit(BTRFS_ROOT_SHAREABLE, &root->state))) {
+		btrfs_put_root(root);
+		return -EUCLEAN;
+	}
 
 	if (btrfs_root_level(&root->root_item) == cur->level) {
 		/* Tree root */
@@ -3403,8 +3371,15 @@ static int handle_indirect_tree_backref(struct btrfs_trans_handle *trans,
 				goto out;
 			}
 			upper->owner = btrfs_header_owner(eb);
-			if (!test_bit(BTRFS_ROOT_SHAREABLE, &root->state))
-				upper->cowonly = 1;
+
+			/* We shouldn't be using backref cache for non shareable roots. */
+			if (unlikely(!test_bit(BTRFS_ROOT_SHAREABLE, &root->state))) {
+				btrfs_put_root(root);
+				btrfs_backref_free_edge(cache, edge);
+				btrfs_backref_free_node(cache, upper);
+				ret = -EUCLEAN;
+				goto out;
+			}
 
 			/*
 			 * If we know the block isn't shared we can avoid
@@ -3595,15 +3570,9 @@ int btrfs_backref_finish_upper_links(struct btrfs_backref_cache *cache,
 
 	ASSERT(start->checked);
 
-	/* Insert this node to cache if it's not COW-only */
-	if (!start->cowonly) {
-		rb_node = rb_simple_insert(&cache->rb_root, start->bytenr,
-					   &start->rb_node);
-		if (rb_node)
-			btrfs_backref_panic(cache->fs_info, start->bytenr,
-					    -EEXIST);
-		list_add_tail(&start->lower, &cache->leaves);
-	}
+	rb_node = rb_simple_insert(&cache->rb_root, start->bytenr, &start->rb_node);
+	if (rb_node)
+		btrfs_backref_panic(cache->fs_info, start->bytenr, -EEXIST);
 
 	/*
 	 * Use breadth first search to iterate all related edges.
@@ -3642,11 +3611,6 @@ int btrfs_backref_finish_upper_links(struct btrfs_backref_cache *cache,
 		 * parents have already been linked.
 		 */
 		if (!RB_EMPTY_NODE(&upper->rb_node)) {
-			if (upper->lowest) {
-				list_del_init(&upper->lower);
-				upper->lowest = 0;
-			}
-
 			list_add_tail(&edge->list[UPPER], &upper->lower);
 			continue;
 		}
@@ -3657,23 +3621,13 @@ int btrfs_backref_finish_upper_links(struct btrfs_backref_cache *cache,
 			return -EUCLEAN;
 		}
 
-		/* Sanity check, COW-only node has non-COW-only parent */
-		if (start->cowonly != upper->cowonly) {
-			ASSERT(0);
+		rb_node = rb_simple_insert(&cache->rb_root, upper->bytenr,
+					   &upper->rb_node);
+		if (unlikely(rb_node)) {
+			btrfs_backref_panic(cache->fs_info, upper->bytenr, -EEXIST);
 			return -EUCLEAN;
 		}
 
-		/* Only cache non-COW-only (subvolume trees) tree blocks */
-		if (!upper->cowonly) {
-			rb_node = rb_simple_insert(&cache->rb_root, upper->bytenr,
-						   &upper->rb_node);
-			if (rb_node) {
-				btrfs_backref_panic(cache->fs_info,
-						upper->bytenr, -EEXIST);
-				return -EUCLEAN;
-			}
-		}
-
 		list_add_tail(&edge->list[UPPER], &upper->lower);
 
 		/*
diff --git a/fs/btrfs/backref.h b/fs/btrfs/backref.h
index e8c22cc..74e6140 100644
--- a/fs/btrfs/backref.h
+++ b/fs/btrfs/backref.h
@@ -318,6 +318,12 @@ struct btrfs_backref_node {
 		u64 bytenr;
 	}; /* Use rb_simple_node for search/insert */
 
+	/*
+	 * This is a sanity check, whenever we COW a block we will update
+	 * new_bytenr with it's current location, and we will check this in
+	 * various places to validate that the cache makes sense, it shouldn't
+	 * be used for anything else.
+	 */
 	u64 new_bytenr;
 	/* Objectid of tree block owner, can be not uptodate */
 	u64 owner;
@@ -335,10 +341,6 @@ struct btrfs_backref_node {
 	struct extent_buffer *eb;
 	/* Level of the tree block */
 	unsigned int level:8;
-	/* Is the block in a non-shareable tree */
-	unsigned int cowonly:1;
-	/* 1 if no child node is in the cache */
-	unsigned int lowest:1;
 	/* Is the extent buffer locked */
 	unsigned int locked:1;
 	/* Has the block been processed */
@@ -391,12 +393,6 @@ struct btrfs_backref_cache {
 	 * level blocks may not reflect the new location
 	 */
 	struct list_head pending[BTRFS_MAX_LEVEL];
-	/* List of backref nodes with no child node */
-	struct list_head leaves;
-	/* List of blocks that have been COWed in current transaction */
-	struct list_head changed;
-	/* List of detached backref node. */
-	struct list_head detached;
 
 	u64 last_trans;
 
diff --git a/fs/btrfs/bio.c b/fs/btrfs/bio.c
index 7ea6f0b..bc2555c 100644
--- a/fs/btrfs/bio.c
+++ b/fs/btrfs/bio.c
@@ -453,6 +453,14 @@ static void btrfs_submit_dev_bio(struct btrfs_device *dev, struct bio *bio)
 		(unsigned long)dev->bdev->bd_dev, btrfs_dev_name(dev),
 		dev->devid, bio->bi_iter.bi_size);
 
+	/*
+	 * Track reads if tracking is enabled; ignore I/O operations before the
+	 * filesystem is fully initialized.
+	 */
+	if (dev->fs_devices->collect_fs_stats && bio_op(bio) == REQ_OP_READ && dev->fs_info)
+		percpu_counter_add(&dev->fs_info->stats_read_blocks,
+				   bio->bi_iter.bi_size >> dev->fs_info->sectorsize_bits);
+
 	if (bio->bi_opf & REQ_BTRFS_CGROUP_PUNT)
 		blkcg_punt_bio_submit(bio);
 	else
@@ -725,8 +733,7 @@ static bool btrfs_submit_chunk(struct btrfs_bio *bbio, int mirror_num)
 			bio->bi_opf |= REQ_OP_ZONE_APPEND;
 		}
 
-		if (is_data_bbio(bbio) && bioc &&
-		    btrfs_need_stripe_tree_update(bioc->fs_info, bioc->map_type)) {
+		if (is_data_bbio(bbio) && bioc && bioc->use_rst) {
 			/*
 			 * No locking for the list update, as we only add to
 			 * the list in the I/O submission path, and list
diff --git a/fs/btrfs/block-group.c b/fs/btrfs/block-group.c
index 4427c1b..c0a8f7d 100644
--- a/fs/btrfs/block-group.c
+++ b/fs/btrfs/block-group.c
@@ -173,43 +173,41 @@ void btrfs_put_block_group(struct btrfs_block_group *cache)
 	}
 }
 
+static int btrfs_bg_start_cmp(const struct rb_node *new,
+			      const struct rb_node *exist)
+{
+	const struct btrfs_block_group *new_bg =
+		rb_entry(new, struct btrfs_block_group, cache_node);
+	const struct btrfs_block_group *exist_bg =
+		rb_entry(exist, struct btrfs_block_group, cache_node);
+
+	if (new_bg->start < exist_bg->start)
+		return -1;
+	if (new_bg->start > exist_bg->start)
+		return 1;
+	return 0;
+}
+
 /*
  * This adds the block group to the fs_info rb tree for the block group cache
  */
 static int btrfs_add_block_group_cache(struct btrfs_fs_info *info,
 				       struct btrfs_block_group *block_group)
 {
-	struct rb_node **p;
-	struct rb_node *parent = NULL;
-	struct btrfs_block_group *cache;
-	bool leftmost = true;
+	struct rb_node *exist;
+	int ret = 0;
 
 	ASSERT(block_group->length != 0);
 
 	write_lock(&info->block_group_cache_lock);
-	p = &info->block_group_cache_tree.rb_root.rb_node;
 
-	while (*p) {
-		parent = *p;
-		cache = rb_entry(parent, struct btrfs_block_group, cache_node);
-		if (block_group->start < cache->start) {
-			p = &(*p)->rb_left;
-		} else if (block_group->start > cache->start) {
-			p = &(*p)->rb_right;
-			leftmost = false;
-		} else {
-			write_unlock(&info->block_group_cache_lock);
-			return -EEXIST;
-		}
-	}
-
-	rb_link_node(&block_group->cache_node, parent, p);
-	rb_insert_color_cached(&block_group->cache_node,
-			       &info->block_group_cache_tree, leftmost);
-
+	exist = rb_find_add_cached(&block_group->cache_node,
+			&info->block_group_cache_tree, btrfs_bg_start_cmp);
+	if (exist)
+		ret = -EEXIST;
 	write_unlock(&info->block_group_cache_lock);
 
-	return 0;
+	return ret;
 }
 
 /*
@@ -1223,7 +1221,7 @@ int btrfs_remove_block_group(struct btrfs_trans_handle *trans,
 	block_group->space_info->total_bytes -= block_group->length;
 	block_group->space_info->bytes_readonly -=
 		(block_group->length - block_group->zone_unusable);
-	btrfs_space_info_update_bytes_zone_unusable(fs_info, block_group->space_info,
+	btrfs_space_info_update_bytes_zone_unusable(block_group->space_info,
 						    -block_group->zone_unusable);
 	block_group->space_info->disk_total -= block_group->length * factor;
 
@@ -1396,8 +1394,7 @@ static int inc_block_group_ro(struct btrfs_block_group *cache, int force)
 		if (btrfs_is_zoned(cache->fs_info)) {
 			/* Migrate zone_unusable bytes to readonly */
 			sinfo->bytes_readonly += cache->zone_unusable;
-			btrfs_space_info_update_bytes_zone_unusable(cache->fs_info, sinfo,
-								    -cache->zone_unusable);
+			btrfs_space_info_update_bytes_zone_unusable(sinfo, -cache->zone_unusable);
 			cache->zone_unusable = 0;
 		}
 		cache->ro++;
@@ -1645,8 +1642,7 @@ void btrfs_delete_unused_bgs(struct btrfs_fs_info *fs_info)
 		spin_lock(&space_info->lock);
 		spin_lock(&block_group->lock);
 
-		btrfs_space_info_update_bytes_pinned(fs_info, space_info,
-						     -block_group->pinned);
+		btrfs_space_info_update_bytes_pinned(space_info, -block_group->pinned);
 		space_info->bytes_readonly += block_group->pinned;
 		block_group->pinned = 0;
 
@@ -2672,7 +2668,6 @@ static int insert_dev_extent(struct btrfs_trans_handle *trans,
 	btrfs_set_dev_extent_chunk_offset(leaf, extent, chunk_offset);
 
 	btrfs_set_dev_extent_length(leaf, extent, num_bytes);
-	btrfs_mark_buffer_dirty(trans, leaf);
 out:
 	btrfs_free_path(path);
 	return ret;
@@ -3060,8 +3055,7 @@ void btrfs_dec_block_group_ro(struct btrfs_block_group *cache)
 				(cache->alloc_offset - cache->used - cache->pinned -
 				 cache->reserved) +
 				(cache->length - cache->zone_capacity);
-			btrfs_space_info_update_bytes_zone_unusable(cache->fs_info, sinfo,
-								    cache->zone_unusable);
+			btrfs_space_info_update_bytes_zone_unusable(sinfo, cache->zone_unusable);
 			sinfo->bytes_readonly -= cache->zone_unusable;
 		}
 		num_bytes = cache->length - cache->reserved -
@@ -3123,7 +3117,6 @@ static int update_block_group_item(struct btrfs_trans_handle *trans,
 						   cache->global_root_id);
 	btrfs_set_stack_block_group_flags(&bgi, cache->flags);
 	write_extent_buffer(leaf, &bgi, bi, sizeof(bgi));
-	btrfs_mark_buffer_dirty(trans, leaf);
 fail:
 	btrfs_release_path(path);
 	/*
@@ -3699,7 +3692,7 @@ int btrfs_update_block_group(struct btrfs_trans_handle *trans,
 		old_val -= num_bytes;
 		cache->used = old_val;
 		cache->pinned += num_bytes;
-		btrfs_space_info_update_bytes_pinned(info, space_info, num_bytes);
+		btrfs_space_info_update_bytes_pinned(space_info, num_bytes);
 		space_info->bytes_used -= num_bytes;
 		space_info->disk_used -= num_bytes * factor;
 		if (READ_ONCE(space_info->periodic_reclaim))
@@ -3781,8 +3774,7 @@ int btrfs_add_reserved_bytes(struct btrfs_block_group *cache,
 	space_info->bytes_reserved += num_bytes;
 	trace_btrfs_space_reservation(cache->fs_info, "space_info",
 				      space_info->flags, num_bytes, 1);
-	btrfs_space_info_update_bytes_may_use(cache->fs_info,
-					      space_info, -ram_bytes);
+	btrfs_space_info_update_bytes_may_use(space_info, -ram_bytes);
 	if (delalloc)
 		cache->delalloc_bytes += num_bytes;
 
diff --git a/fs/btrfs/block-rsv.c b/fs/btrfs/block-rsv.c
index a07b959..3f36082 100644
--- a/fs/btrfs/block-rsv.c
+++ b/fs/btrfs/block-rsv.c
@@ -150,9 +150,7 @@ static u64 block_rsv_release_bytes(struct btrfs_fs_info *fs_info,
 			spin_unlock(&dest->lock);
 		}
 		if (num_bytes)
-			btrfs_space_info_free_bytes_may_use(fs_info,
-							    space_info,
-							    num_bytes);
+			btrfs_space_info_free_bytes_may_use(space_info, num_bytes);
 	}
 	if (qgroup_to_release_ret)
 		*qgroup_to_release_ret = qgroup_to_release;
@@ -383,13 +381,11 @@ void btrfs_update_global_block_rsv(struct btrfs_fs_info *fs_info)
 
 	if (block_rsv->reserved < block_rsv->size) {
 		num_bytes = block_rsv->size - block_rsv->reserved;
-		btrfs_space_info_update_bytes_may_use(fs_info, sinfo,
-						      num_bytes);
+		btrfs_space_info_update_bytes_may_use(sinfo, num_bytes);
 		block_rsv->reserved = block_rsv->size;
 	} else if (block_rsv->reserved > block_rsv->size) {
 		num_bytes = block_rsv->reserved - block_rsv->size;
-		btrfs_space_info_update_bytes_may_use(fs_info, sinfo,
-						      -num_bytes);
+		btrfs_space_info_update_bytes_may_use(sinfo, -num_bytes);
 		block_rsv->reserved = block_rsv->size;
 		btrfs_try_granting_tickets(fs_info, sinfo);
 	}
diff --git a/fs/btrfs/btrfs_inode.h b/fs/btrfs/btrfs_inode.h
index aa1f55c..b2fa339 100644
--- a/fs/btrfs/btrfs_inode.h
+++ b/fs/btrfs/btrfs_inode.h
@@ -526,7 +526,7 @@ bool btrfs_data_csum_ok(struct btrfs_bio *bbio, struct btrfs_device *dev,
 			u32 bio_offset, struct bio_vec *bv);
 noinline int can_nocow_extent(struct inode *inode, u64 offset, u64 *len,
 			      struct btrfs_file_extent *file_extent,
-			      bool nowait, bool strict);
+			      bool nowait);
 
 void btrfs_del_delalloc_inode(struct btrfs_inode *inode);
 struct inode *btrfs_lookup_dentry(struct inode *dir, struct dentry *dentry);
diff --git a/fs/btrfs/ctree.c b/fs/btrfs/ctree.c
index 185985a..3dc5a35 100644
--- a/fs/btrfs/ctree.c
+++ b/fs/btrfs/ctree.c
@@ -37,19 +37,6 @@ static int push_node_left(struct btrfs_trans_handle *trans,
 static int balance_node_right(struct btrfs_trans_handle *trans,
 			      struct extent_buffer *dst_buf,
 			      struct extent_buffer *src_buf);
-
-static const struct btrfs_csums {
-	u16		size;
-	const char	name[10];
-	const char	driver[12];
-} btrfs_csums[] = {
-	[BTRFS_CSUM_TYPE_CRC32] = { .size = 4, .name = "crc32c" },
-	[BTRFS_CSUM_TYPE_XXHASH] = { .size = 8, .name = "xxhash64" },
-	[BTRFS_CSUM_TYPE_SHA256] = { .size = 32, .name = "sha256" },
-	[BTRFS_CSUM_TYPE_BLAKE2] = { .size = 32, .name = "blake2b",
-				     .driver = "blake2b-256" },
-};
-
 /*
  * The leaf data grows from end-to-front in the node.  this returns the address
  * of the start of the last item, which is the stop of the leaf data stack.
@@ -148,44 +135,6 @@ static inline void copy_leaf_items(const struct extent_buffer *dst,
 			      nr_items * sizeof(struct btrfs_item));
 }
 
-/* This exists for btrfs-progs usages. */
-u16 btrfs_csum_type_size(u16 type)
-{
-	return btrfs_csums[type].size;
-}
-
-int btrfs_super_csum_size(const struct btrfs_super_block *s)
-{
-	u16 t = btrfs_super_csum_type(s);
-	/*
-	 * csum type is validated at mount time
-	 */
-	return btrfs_csum_type_size(t);
-}
-
-const char *btrfs_super_csum_name(u16 csum_type)
-{
-	/* csum type is validated at mount time */
-	return btrfs_csums[csum_type].name;
-}
-
-/*
- * Return driver name if defined, otherwise the name that's also a valid driver
- * name
- */
-const char *btrfs_super_csum_driver(u16 csum_type)
-{
-	/* csum type is validated at mount time */
-	return btrfs_csums[csum_type].driver[0] ?
-		btrfs_csums[csum_type].driver :
-		btrfs_csums[csum_type].name;
-}
-
-size_t __attribute_const__ btrfs_get_num_csums(void)
-{
-	return ARRAY_SIZE(btrfs_csums);
-}
-
 struct btrfs_path *btrfs_alloc_path(void)
 {
 	might_sleep();
@@ -226,22 +175,6 @@ noinline void btrfs_release_path(struct btrfs_path *p)
 }
 
 /*
- * We want the transaction abort to print stack trace only for errors where the
- * cause could be a bug, eg. due to ENOSPC, and not for common errors that are
- * caused by external factors.
- */
-bool __cold abort_should_print_stack(int error)
-{
-	switch (error) {
-	case -EIO:
-	case -EROFS:
-	case -ENOMEM:
-		return false;
-	}
-	return true;
-}
-
-/*
  * safely gets a reference on the root node of a tree.  A lock
  * is not taken, so a concurrent writer may put a different node
  * at the root of the tree.  See btrfs_lock_root_node for the
@@ -1563,6 +1496,7 @@ read_block_for_search(struct btrfs_root *root, struct btrfs_path *p,
 
 		if (!p->skip_locking) {
 			btrfs_unlock_up_safe(p, parent_level + 1);
+			btrfs_maybe_reset_lockdep_class(root, tmp);
 			tmp_locked = true;
 			btrfs_tree_read_lock(tmp);
 			btrfs_release_path(p);
@@ -1606,6 +1540,7 @@ read_block_for_search(struct btrfs_root *root, struct btrfs_path *p,
 
 	if (!p->skip_locking) {
 		ASSERT(ret == -EAGAIN);
+		btrfs_maybe_reset_lockdep_class(root, tmp);
 		tmp_locked = true;
 		btrfs_tree_read_lock(tmp);
 		btrfs_release_path(p);
@@ -3900,6 +3835,7 @@ static noinline int setup_leaf_for_split(struct btrfs_trans_handle *trans,
 	btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
 
 	BUG_ON(key.type != BTRFS_EXTENT_DATA_KEY &&
+	       key.type != BTRFS_RAID_STRIPE_KEY &&
 	       key.type != BTRFS_EXTENT_CSUM_KEY);
 
 	if (btrfs_leaf_free_space(leaf) >= ins_len)
diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h
index 2c34195..1096a80 100644
--- a/fs/btrfs/ctree.h
+++ b/fs/btrfs/ctree.h
@@ -7,7 +7,6 @@
 #define BTRFS_CTREE_H
 
 #include "linux/cleanup.h"
-#include <linux/pagemap.h>
 #include <linux/spinlock.h>
 #include <linux/rbtree.h>
 #include <linux/mutex.h>
@@ -506,20 +505,6 @@ static inline u32 BTRFS_MAX_XATTR_SIZE(const struct btrfs_fs_info *info)
 	return BTRFS_MAX_ITEM_SIZE(info) - sizeof(struct btrfs_dir_item);
 }
 
-#define BTRFS_BYTES_TO_BLKS(fs_info, bytes) \
-				((bytes) >> (fs_info)->sectorsize_bits)
-
-static inline gfp_t btrfs_alloc_write_mask(struct address_space *mapping)
-{
-	return mapping_gfp_constraint(mapping, ~__GFP_FS);
-}
-
-void btrfs_error_unpin_extent_range(struct btrfs_fs_info *fs_info, u64 start, u64 end);
-int btrfs_discard_extent(struct btrfs_fs_info *fs_info, u64 bytenr,
-			 u64 num_bytes, u64 *actual_bytes);
-int btrfs_trim_fs(struct btrfs_fs_info *fs_info, struct fstrim_range *range);
-
-/* ctree.c */
 int __init btrfs_ctree_init(void);
 void __cold btrfs_ctree_exit(void);
 
@@ -756,18 +741,4 @@ static inline bool btrfs_is_data_reloc_root(const struct btrfs_root *root)
 	return root->root_key.objectid == BTRFS_DATA_RELOC_TREE_OBJECTID;
 }
 
-u16 btrfs_csum_type_size(u16 type);
-int btrfs_super_csum_size(const struct btrfs_super_block *s);
-const char *btrfs_super_csum_name(u16 csum_type);
-const char *btrfs_super_csum_driver(u16 csum_type);
-size_t __attribute_const__ btrfs_get_num_csums(void);
-
-/*
- * We use folio flag owner_2 to indicate there is an ordered extent with
- * unfinished IO.
- */
-#define folio_test_ordered(folio)	folio_test_owner_2(folio)
-#define folio_set_ordered(folio)	folio_set_owner_2(folio)
-#define folio_clear_ordered(folio)	folio_clear_owner_2(folio)
-
 #endif
diff --git a/fs/btrfs/delalloc-space.c b/fs/btrfs/delalloc-space.c
index 7aa8a39..88e900e 100644
--- a/fs/btrfs/delalloc-space.c
+++ b/fs/btrfs/delalloc-space.c
@@ -176,7 +176,7 @@ void btrfs_free_reserved_data_space_noquota(struct btrfs_fs_info *fs_info,
 	ASSERT(IS_ALIGNED(len, fs_info->sectorsize));
 
 	data_sinfo = fs_info->data_sinfo;
-	btrfs_space_info_free_bytes_may_use(fs_info, data_sinfo, len);
+	btrfs_space_info_free_bytes_may_use(data_sinfo, len);
 }
 
 /*
diff --git a/fs/btrfs/delayed-inode.c b/fs/btrfs/delayed-inode.c
index 508bdba..0b4933c 100644
--- a/fs/btrfs/delayed-inode.c
+++ b/fs/btrfs/delayed-inode.c
@@ -366,40 +366,35 @@ static struct btrfs_delayed_item *__btrfs_lookup_delayed_item(
 	return NULL;
 }
 
+static int btrfs_delayed_item_cmp(const struct rb_node *new,
+				  const struct rb_node *exist)
+{
+	const struct btrfs_delayed_item *new_item =
+		rb_entry(new, struct btrfs_delayed_item, rb_node);
+	const struct btrfs_delayed_item *exist_item =
+		rb_entry(exist, struct btrfs_delayed_item, rb_node);
+
+	if (new_item->index < exist_item->index)
+		return -1;
+	if (new_item->index > exist_item->index)
+		return 1;
+	return 0;
+}
+
 static int __btrfs_add_delayed_item(struct btrfs_delayed_node *delayed_node,
 				    struct btrfs_delayed_item *ins)
 {
-	struct rb_node **p, *node;
-	struct rb_node *parent_node = NULL;
 	struct rb_root_cached *root;
-	struct btrfs_delayed_item *item;
-	bool leftmost = true;
+	struct rb_node *exist;
 
 	if (ins->type == BTRFS_DELAYED_INSERTION_ITEM)
 		root = &delayed_node->ins_root;
 	else
 		root = &delayed_node->del_root;
 
-	p = &root->rb_root.rb_node;
-	node = &ins->rb_node;
-
-	while (*p) {
-		parent_node = *p;
-		item = rb_entry(parent_node, struct btrfs_delayed_item,
-				 rb_node);
-
-		if (item->index < ins->index) {
-			p = &(*p)->rb_right;
-			leftmost = false;
-		} else if (item->index > ins->index) {
-			p = &(*p)->rb_left;
-		} else {
-			return -EEXIST;
-		}
-	}
-
-	rb_link_node(node, parent_node, p);
-	rb_insert_color_cached(node, root, leftmost);
+	exist = rb_find_add_cached(&ins->rb_node, root, btrfs_delayed_item_cmp);
+	if (exist)
+		return -EEXIST;
 
 	if (ins->type == BTRFS_DELAYED_INSERTION_ITEM &&
 	    ins->index >= delayed_node->index_cnt)
@@ -1038,7 +1033,6 @@ static int __btrfs_update_delayed_inode(struct btrfs_trans_handle *trans,
 				    struct btrfs_inode_item);
 	write_extent_buffer(leaf, &node->inode_item, (unsigned long)inode_item,
 			    sizeof(struct btrfs_inode_item));
-	btrfs_mark_buffer_dirty(trans, leaf);
 
 	if (!test_bit(BTRFS_DELAYED_NODE_DEL_IREF, &node->flags))
 		goto out;
@@ -1561,8 +1555,7 @@ int btrfs_insert_delayed_dir_index(struct btrfs_trans_handle *trans,
 	return ret;
 }
 
-static int btrfs_delete_delayed_insertion_item(struct btrfs_fs_info *fs_info,
-					       struct btrfs_delayed_node *node,
+static int btrfs_delete_delayed_insertion_item(struct btrfs_delayed_node *node,
 					       u64 index)
 {
 	struct btrfs_delayed_item *item;
@@ -1620,7 +1613,7 @@ int btrfs_delete_delayed_dir_index(struct btrfs_trans_handle *trans,
 	if (IS_ERR(node))
 		return PTR_ERR(node);
 
-	ret = btrfs_delete_delayed_insertion_item(trans->fs_info, node, index);
+	ret = btrfs_delete_delayed_insertion_item(node, index);
 	if (!ret)
 		goto end;
 
diff --git a/fs/btrfs/delayed-ref.c b/fs/btrfs/delayed-ref.c
index 0d878db..98c5b61 100644
--- a/fs/btrfs/delayed-ref.c
+++ b/fs/btrfs/delayed-ref.c
@@ -93,6 +93,9 @@ void btrfs_update_delayed_refs_rsv(struct btrfs_trans_handle *trans)
 	u64 num_bytes;
 	u64 reserved_bytes;
 
+	if (btrfs_is_testing(fs_info))
+		return;
+
 	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);
@@ -254,7 +257,7 @@ 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, space_info, to_free);
+		btrfs_space_info_free_bytes_may_use(space_info, to_free);
 
 	if (refilled_bytes > 0)
 		trace_btrfs_space_reservation(fs_info, "delayed_refs_rsv", 0,
@@ -265,8 +268,8 @@ int btrfs_delayed_refs_rsv_refill(struct btrfs_fs_info *fs_info,
 /*
  * compare two delayed data backrefs with same bytenr and type
  */
-static int comp_data_refs(struct btrfs_delayed_ref_node *ref1,
-			  struct btrfs_delayed_ref_node *ref2)
+static int comp_data_refs(const struct btrfs_delayed_ref_node *ref1,
+			  const struct btrfs_delayed_ref_node *ref2)
 {
 	if (ref1->data_ref.objectid < ref2->data_ref.objectid)
 		return -1;
@@ -279,8 +282,8 @@ static int comp_data_refs(struct btrfs_delayed_ref_node *ref1,
 	return 0;
 }
 
-static int comp_refs(struct btrfs_delayed_ref_node *ref1,
-		     struct btrfs_delayed_ref_node *ref2,
+static int comp_refs(const struct btrfs_delayed_ref_node *ref1,
+		     const struct btrfs_delayed_ref_node *ref2,
 		     bool check_seq)
 {
 	int ret = 0;
@@ -314,34 +317,25 @@ static int comp_refs(struct btrfs_delayed_ref_node *ref1,
 	return 0;
 }
 
+static int cmp_refs_node(const struct rb_node *new, const struct rb_node *exist)
+{
+	const struct btrfs_delayed_ref_node *new_node =
+		rb_entry(new, struct btrfs_delayed_ref_node, ref_node);
+	const struct btrfs_delayed_ref_node *exist_node =
+		rb_entry(exist, struct btrfs_delayed_ref_node, ref_node);
+
+	return comp_refs(new_node, exist_node, true);
+}
+
 static struct btrfs_delayed_ref_node* tree_insert(struct rb_root_cached *root,
 		struct btrfs_delayed_ref_node *ins)
 {
-	struct rb_node **p = &root->rb_root.rb_node;
 	struct rb_node *node = &ins->ref_node;
-	struct rb_node *parent_node = NULL;
-	struct btrfs_delayed_ref_node *entry;
-	bool leftmost = true;
+	struct rb_node *exist;
 
-	while (*p) {
-		int comp;
-
-		parent_node = *p;
-		entry = rb_entry(parent_node, struct btrfs_delayed_ref_node,
-				 ref_node);
-		comp = comp_refs(ins, entry, true);
-		if (comp < 0) {
-			p = &(*p)->rb_left;
-		} else if (comp > 0) {
-			p = &(*p)->rb_right;
-			leftmost = false;
-		} else {
-			return entry;
-		}
-	}
-
-	rb_link_node(node, parent_node, p);
-	rb_insert_color_cached(node, root, leftmost);
+	exist = rb_find_add_cached(node, root, cmp_refs_node);
+	if (exist)
+		return rb_entry(exist, struct btrfs_delayed_ref_node, ref_node);
 	return NULL;
 }
 
@@ -555,6 +549,32 @@ void btrfs_delete_ref_head(const struct btrfs_fs_info *fs_info,
 		delayed_refs->num_heads_ready--;
 }
 
+struct btrfs_delayed_ref_node *btrfs_select_delayed_ref(struct btrfs_delayed_ref_head *head)
+{
+	struct btrfs_delayed_ref_node *ref;
+
+	lockdep_assert_held(&head->mutex);
+	lockdep_assert_held(&head->lock);
+
+	if (RB_EMPTY_ROOT(&head->ref_tree.rb_root))
+		return NULL;
+
+	/*
+	 * Select a delayed ref of type BTRFS_ADD_DELAYED_REF first.
+	 * This is to prevent a ref count from going down to zero, which deletes
+	 * the extent item from the extent tree, when there still are references
+	 * to add, which would fail because they would not find the extent item.
+	 */
+	if (!list_empty(&head->ref_add_list))
+		return list_first_entry(&head->ref_add_list,
+					struct btrfs_delayed_ref_node, add_list);
+
+	ref = rb_entry(rb_first_cached(&head->ref_tree),
+		       struct btrfs_delayed_ref_node, ref_node);
+	ASSERT(list_empty(&ref->add_list));
+	return ref;
+}
+
 /*
  * Helper to insert the ref_node to the tail or merge with tail.
  *
@@ -1234,6 +1254,7 @@ void btrfs_destroy_delayed_refs(struct btrfs_transaction *trans)
 {
 	struct btrfs_delayed_ref_root *delayed_refs = &trans->delayed_refs;
 	struct btrfs_fs_info *fs_info = trans->fs_info;
+	bool testing = btrfs_is_testing(fs_info);
 
 	spin_lock(&delayed_refs->lock);
 	while (true) {
@@ -1263,7 +1284,7 @@ void btrfs_destroy_delayed_refs(struct btrfs_transaction *trans)
 		spin_unlock(&delayed_refs->lock);
 		mutex_unlock(&head->mutex);
 
-		if (pin_bytes) {
+		if (!testing && pin_bytes) {
 			struct btrfs_block_group *bg;
 
 			bg = btrfs_lookup_block_group(fs_info, head->bytenr);
@@ -1281,8 +1302,7 @@ void btrfs_destroy_delayed_refs(struct btrfs_transaction *trans)
 				spin_lock(&bg->space_info->lock);
 				spin_lock(&bg->lock);
 				bg->pinned += head->num_bytes;
-				btrfs_space_info_update_bytes_pinned(fs_info,
-								     bg->space_info,
+				btrfs_space_info_update_bytes_pinned(bg->space_info,
 								     head->num_bytes);
 				bg->reserved -= head->num_bytes;
 				bg->space_info->bytes_reserved -= head->num_bytes;
@@ -1295,12 +1315,15 @@ void btrfs_destroy_delayed_refs(struct btrfs_transaction *trans)
 			btrfs_error_unpin_extent_range(fs_info, head->bytenr,
 				head->bytenr + head->num_bytes - 1);
 		}
-		btrfs_cleanup_ref_head_accounting(fs_info, delayed_refs, head);
+		if (!testing)
+			btrfs_cleanup_ref_head_accounting(fs_info, delayed_refs, head);
 		btrfs_put_delayed_ref_head(head);
 		cond_resched();
 		spin_lock(&delayed_refs->lock);
 	}
-	btrfs_qgroup_destroy_extent_records(trans);
+
+	if (!testing)
+		btrfs_qgroup_destroy_extent_records(trans);
 
 	spin_unlock(&delayed_refs->lock);
 }
diff --git a/fs/btrfs/delayed-ref.h b/fs/btrfs/delayed-ref.h
index 611fb33..a35067c 100644
--- a/fs/btrfs/delayed-ref.h
+++ b/fs/btrfs/delayed-ref.h
@@ -402,6 +402,7 @@ struct btrfs_delayed_ref_head *btrfs_select_ref_head(
 		struct btrfs_delayed_ref_root *delayed_refs);
 void btrfs_unselect_ref_head(struct btrfs_delayed_ref_root *delayed_refs,
 			     struct btrfs_delayed_ref_head *head);
+struct btrfs_delayed_ref_node *btrfs_select_delayed_ref(struct btrfs_delayed_ref_head *head);
 
 int btrfs_check_delayed_seq(struct btrfs_fs_info *fs_info, u64 seq);
 
diff --git a/fs/btrfs/dev-replace.c b/fs/btrfs/dev-replace.c
index ac8e97e..f86fbea 100644
--- a/fs/btrfs/dev-replace.c
+++ b/fs/btrfs/dev-replace.c
@@ -440,9 +440,6 @@ int btrfs_run_dev_replace(struct btrfs_trans_handle *trans)
 		dev_replace->cursor_right);
 	dev_replace->item_needs_writeback = 0;
 	up_write(&dev_replace->rwsem);
-
-	btrfs_mark_buffer_dirty(trans, eb);
-
 out:
 	btrfs_free_path(path);
 
diff --git a/fs/btrfs/dir-item.c b/fs/btrfs/dir-item.c
index 1ea5d8f..ccf91de 100644
--- a/fs/btrfs/dir-item.c
+++ b/fs/btrfs/dir-item.c
@@ -92,7 +92,6 @@ int btrfs_insert_xattr_item(struct btrfs_trans_handle *trans,
 
 	write_extent_buffer(leaf, name, name_ptr, name_len);
 	write_extent_buffer(leaf, data, data_ptr, data_len);
-	btrfs_mark_buffer_dirty(trans, path->nodes[0]);
 
 	return ret;
 }
@@ -152,7 +151,6 @@ int btrfs_insert_dir_item(struct btrfs_trans_handle *trans,
 	name_ptr = (unsigned long)(dir_item + 1);
 
 	write_extent_buffer(leaf, name->name, name_ptr, name->len);
-	btrfs_mark_buffer_dirty(trans, leaf);
 
 second_insert:
 	/* FIXME, use some real flag for selecting the extra index */
diff --git a/fs/btrfs/direct-io.c b/fs/btrfs/direct-io.c
index a7c3e22..8567af4 100644
--- a/fs/btrfs/direct-io.c
+++ b/fs/btrfs/direct-io.c
@@ -248,8 +248,7 @@ static int btrfs_get_blocks_direct_write(struct extent_map **map,
 		len = min(len, em->len - (start - em->start));
 		block_start = extent_map_block_start(em) + (start - em->start);
 
-		if (can_nocow_extent(inode, start, &len,
-				     &file_extent, false, false) == 1) {
+		if (can_nocow_extent(inode, start, &len, &file_extent, false) == 1) {
 			bg = btrfs_inc_nocow_writers(fs_info, block_start);
 			if (bg)
 				can_nocow = true;
diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c
index eff0dd1..f09db62 100644
--- a/fs/btrfs/disk-io.c
+++ b/fs/btrfs/disk-io.c
@@ -226,7 +226,7 @@ int btrfs_read_extent_buffer(struct extent_buffer *eb,
 
 	while (1) {
 		clear_bit(EXTENT_BUFFER_CORRUPT, &eb->bflags);
-		ret = read_extent_buffer_pages(eb, WAIT_COMPLETE, mirror_num, check);
+		ret = read_extent_buffer_pages(eb, mirror_num, check);
 		if (!ret)
 			break;
 
@@ -1258,6 +1258,7 @@ void btrfs_free_fs_info(struct btrfs_fs_info *fs_info)
 {
 	struct percpu_counter *em_counter = &fs_info->evictable_extent_maps;
 
+	percpu_counter_destroy(&fs_info->stats_read_blocks);
 	percpu_counter_destroy(&fs_info->dirty_metadata_bytes);
 	percpu_counter_destroy(&fs_info->delalloc_bytes);
 	percpu_counter_destroy(&fs_info->ordered_bytes);
@@ -2327,6 +2328,71 @@ static int btrfs_read_roots(struct btrfs_fs_info *fs_info)
 	return ret;
 }
 
+static int validate_sys_chunk_array(const struct btrfs_fs_info *fs_info,
+				    const struct btrfs_super_block *sb)
+{
+	unsigned int cur = 0; /* Offset inside the sys chunk array */
+	/*
+	 * At sb read time, fs_info is not fully initialized. Thus we have
+	 * to use super block sectorsize, which should have been validated.
+	 */
+	const u32 sectorsize = btrfs_super_sectorsize(sb);
+	u32 sys_array_size = btrfs_super_sys_array_size(sb);
+
+	if (sys_array_size > BTRFS_SYSTEM_CHUNK_ARRAY_SIZE) {
+		btrfs_err(fs_info, "system chunk array too big %u > %u",
+			  sys_array_size, BTRFS_SYSTEM_CHUNK_ARRAY_SIZE);
+		return -EUCLEAN;
+	}
+
+	while (cur < sys_array_size) {
+		struct btrfs_disk_key *disk_key;
+		struct btrfs_chunk *chunk;
+		struct btrfs_key key;
+		u64 type;
+		u16 num_stripes;
+		u32 len;
+		int ret;
+
+		disk_key = (struct btrfs_disk_key *)(sb->sys_chunk_array + cur);
+		len = sizeof(*disk_key);
+
+		if (cur + len > sys_array_size)
+			goto short_read;
+		cur += len;
+
+		btrfs_disk_key_to_cpu(&key, disk_key);
+		if (key.type != BTRFS_CHUNK_ITEM_KEY) {
+			btrfs_err(fs_info,
+			    "unexpected item type %u in sys_array at offset %u",
+				  key.type, cur);
+			return -EUCLEAN;
+		}
+		chunk = (struct btrfs_chunk *)(sb->sys_chunk_array + cur);
+		num_stripes = btrfs_stack_chunk_num_stripes(chunk);
+		if (cur + btrfs_chunk_item_size(num_stripes) > sys_array_size)
+			goto short_read;
+		type = btrfs_stack_chunk_type(chunk);
+		if (!(type & BTRFS_BLOCK_GROUP_SYSTEM)) {
+			btrfs_err(fs_info,
+			"invalid chunk type %llu in sys_array at offset %u",
+				  type, cur);
+			return -EUCLEAN;
+		}
+		ret = btrfs_check_chunk_valid(fs_info, NULL, chunk, key.offset,
+					      sectorsize);
+		if (ret < 0)
+			return ret;
+		cur += btrfs_chunk_item_size(num_stripes);
+	}
+	return 0;
+short_read:
+	btrfs_err(fs_info,
+	"super block sys chunk array short read, cur=%u sys_array_size=%u",
+		  cur, sys_array_size);
+	return -EUCLEAN;
+}
+
 /*
  * Real super block validation
  * NOTE: super csum type and incompat features will not be checked here.
@@ -2495,6 +2561,8 @@ int btrfs_validate_super(const struct btrfs_fs_info *fs_info,
 		ret = -EINVAL;
 	}
 
+	ret = validate_sys_chunk_array(fs_info, sb);
+
 	/*
 	 * Obvious sys_chunk_array corruptions, it must hold at least one key
 	 * and one chunk
@@ -2856,6 +2924,10 @@ static int init_mount_fs_info(struct btrfs_fs_info *fs_info, struct super_block
 	if (ret)
 		return ret;
 
+	ret = percpu_counter_init(&fs_info->stats_read_blocks, 0, GFP_KERNEL);
+	if (ret)
+		return ret;
+
 	fs_info->dirty_metadata_batch = PAGE_SIZE *
 					(1 + ilog2(nr_cpu_ids));
 
@@ -3321,6 +3393,7 @@ int __cold open_ctree(struct super_block *sb, struct btrfs_fs_devices *fs_device
 	fs_info->sectors_per_page = (PAGE_SIZE >> fs_info->sectorsize_bits);
 	fs_info->csums_per_leaf = BTRFS_MAX_ITEM_SIZE(fs_info) / fs_info->csum_size;
 	fs_info->stripesize = stripesize;
+	fs_info->fs_devices->fs_info = fs_info;
 
 	/*
 	 * Handle the space caching options appropriately now that we have the
diff --git a/fs/btrfs/disk-io.h b/fs/btrfs/disk-io.h
index a7051e2..5878429 100644
--- a/fs/btrfs/disk-io.h
+++ b/fs/btrfs/disk-io.h
@@ -96,9 +96,6 @@ struct btrfs_root *btrfs_alloc_dummy_root(struct btrfs_fs_info *fs_info);
 /*
  * This function is used to grab the root, and avoid it is freed when we
  * access it. But it doesn't ensure that the tree is not dropped.
- *
- * If you want to ensure the whole tree is safe, you should use
- * 	fs_info->subvol_srcu
  */
 static inline struct btrfs_root *btrfs_grab_root(struct btrfs_root *root)
 {
diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c
index 3c6f7fe..3014a1a 100644
--- a/fs/btrfs/extent-tree.c
+++ b/fs/btrfs/extent-tree.c
@@ -570,7 +570,6 @@ static noinline int insert_extent_data_ref(struct btrfs_trans_handle *trans,
 			btrfs_set_extent_data_ref_count(leaf, ref, num_refs);
 		}
 	}
-	btrfs_mark_buffer_dirty(trans, leaf);
 	ret = 0;
 fail:
 	btrfs_release_path(path);
@@ -618,7 +617,6 @@ static noinline int remove_extent_data_ref(struct btrfs_trans_handle *trans,
 			btrfs_set_extent_data_ref_count(leaf, ref1, num_refs);
 		else if (key.type == BTRFS_SHARED_DATA_REF_KEY)
 			btrfs_set_shared_data_ref_count(leaf, ref2, num_refs);
-		btrfs_mark_buffer_dirty(trans, leaf);
 	}
 	return ret;
 }
@@ -1050,7 +1048,6 @@ void setup_inline_extent_backref(struct btrfs_trans_handle *trans,
 	} else {
 		btrfs_set_extent_inline_ref_offset(leaf, iref, root_objectid);
 	}
-	btrfs_mark_buffer_dirty(trans, leaf);
 }
 
 static int lookup_extent_backref(struct btrfs_trans_handle *trans,
@@ -1195,7 +1192,6 @@ static noinline_for_stack int update_inline_extent_backref(
 		item_size -= size;
 		btrfs_truncate_item(trans, path, item_size, 1);
 	}
-	btrfs_mark_buffer_dirty(trans, leaf);
 	return 0;
 }
 
@@ -1260,12 +1256,12 @@ static int btrfs_issue_discard(struct block_device *bdev, u64 start, u64 len,
 {
 	int j, ret = 0;
 	u64 bytes_left, end;
-	u64 aligned_start = ALIGN(start, 1 << SECTOR_SHIFT);
+	u64 aligned_start = ALIGN(start, SECTOR_SIZE);
 
 	/* Adjust the range to be aligned to 512B sectors if necessary. */
 	if (start != aligned_start) {
 		len -= aligned_start - start;
-		len = round_down(len, 1 << SECTOR_SHIFT);
+		len = round_down(len, SECTOR_SIZE);
 		start = aligned_start;
 	}
 
@@ -1527,7 +1523,6 @@ static int __btrfs_inc_extent_ref(struct btrfs_trans_handle *trans,
 	if (extent_op)
 		__run_delayed_extent_op(extent_op, leaf, item);
 
-	btrfs_mark_buffer_dirty(trans, leaf);
 	btrfs_release_path(path);
 
 	/* now insert the actual backref */
@@ -1711,8 +1706,6 @@ static int run_delayed_extent_op(struct btrfs_trans_handle *trans,
 
 	ei = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
 	__run_delayed_extent_op(extent_op, leaf, ei);
-
-	btrfs_mark_buffer_dirty(trans, leaf);
 out:
 	btrfs_free_path(path);
 	return ret;
@@ -1803,30 +1796,6 @@ static int run_one_delayed_ref(struct btrfs_trans_handle *trans,
 	return ret;
 }
 
-static inline struct btrfs_delayed_ref_node *
-select_delayed_ref(struct btrfs_delayed_ref_head *head)
-{
-	struct btrfs_delayed_ref_node *ref;
-
-	if (RB_EMPTY_ROOT(&head->ref_tree.rb_root))
-		return NULL;
-
-	/*
-	 * Select a delayed ref of type BTRFS_ADD_DELAYED_REF first.
-	 * This is to prevent a ref count from going down to zero, which deletes
-	 * the extent item from the extent tree, when there still are references
-	 * to add, which would fail because they would not find the extent item.
-	 */
-	if (!list_empty(&head->ref_add_list))
-		return list_first_entry(&head->ref_add_list,
-				struct btrfs_delayed_ref_node, add_list);
-
-	ref = rb_entry(rb_first_cached(&head->ref_tree),
-		       struct btrfs_delayed_ref_node, ref_node);
-	ASSERT(list_empty(&ref->add_list));
-	return ref;
-}
-
 static struct btrfs_delayed_extent_op *cleanup_extent_op(
 				struct btrfs_delayed_ref_head *head)
 {
@@ -1959,7 +1928,7 @@ static int btrfs_run_delayed_refs_for_head(struct btrfs_trans_handle *trans,
 	lockdep_assert_held(&locked_ref->mutex);
 	lockdep_assert_held(&locked_ref->lock);
 
-	while ((ref = select_delayed_ref(locked_ref))) {
+	while ((ref = btrfs_select_delayed_ref(locked_ref))) {
 		if (ref->seq &&
 		    btrfs_check_delayed_seq(fs_info, ref->seq)) {
 			spin_unlock(&locked_ref->lock);
@@ -2230,10 +2199,11 @@ int btrfs_set_disk_extent_flags(struct btrfs_trans_handle *trans,
 	return ret;
 }
 
-static noinline int check_delayed_ref(struct btrfs_root *root,
+static noinline int check_delayed_ref(struct btrfs_inode *inode,
 				      struct btrfs_path *path,
-				      u64 objectid, u64 offset, u64 bytenr)
+				      u64 offset, u64 bytenr)
 {
+	struct btrfs_root *root = inode->root;
 	struct btrfs_delayed_ref_head *head;
 	struct btrfs_delayed_ref_node *ref;
 	struct btrfs_delayed_ref_root *delayed_refs;
@@ -2307,7 +2277,7 @@ static noinline int check_delayed_ref(struct btrfs_root *root,
 		 * then we have a cross reference.
 		 */
 		if (ref->ref_root != btrfs_root_id(root) ||
-		    ref_owner != objectid || ref_offset != offset) {
+		    ref_owner != btrfs_ino(inode) || ref_offset != offset) {
 			ret = 1;
 			break;
 		}
@@ -2318,11 +2288,53 @@ static noinline int check_delayed_ref(struct btrfs_root *root,
 	return ret;
 }
 
-static noinline int check_committed_ref(struct btrfs_root *root,
+/*
+ * Check if there are references for a data extent other than the one belonging
+ * to the given inode and offset.
+ *
+ * @inode:     The only inode we expect to find associated with the data extent.
+ * @path:      A path to use for searching the extent tree.
+ * @offset:    The only offset we expect to find associated with the data extent.
+ * @bytenr:    The logical address of the data extent.
+ *
+ * When the extent does not have any other references other than the one we
+ * expect to find, we always return a value of 0 with the path having a locked
+ * leaf that contains the extent's extent item - this is necessary to ensure
+ * we don't race with a task running delayed references, and our caller must
+ * have such a path when calling check_delayed_ref() - it must lock a delayed
+ * ref head while holding the leaf locked. In case the extent item is not found
+ * in the extent tree, we return -ENOENT with the path having the leaf (locked)
+ * where the extent item should be, in order to prevent races with another task
+ * running delayed references, so that we don't miss any reference when calling
+ * check_delayed_ref().
+ *
+ * Note: this may return false positives, and this is because we want to be
+ *       quick here as we're called in write paths (when flushing delalloc and
+ *       in the direct IO write path). For example we can have an extent with
+ *       a single reference but that reference is not inlined, or we may have
+ *       many references in the extent tree but we also have delayed references
+ *       that cancel all the reference except the one for our inode and offset,
+ *       but it would be expensive to do such checks and complex due to all
+ *       locking to avoid races between the checks and flushing delayed refs,
+ *       plus non-inline references may be located on leaves other than the one
+ *       that contains the extent item in the extent tree. The important thing
+ *       here is to not return false negatives and that the false positives are
+ *       not very common.
+ *
+ * Returns: 0 if there are no cross references and with the path having a locked
+ *          leaf from the extent tree that contains the extent's extent item.
+ *
+ *          1 if there are cross references (false positives can happen).
+ *
+ *          < 0 in case of an error. In case of -ENOENT the leaf in the extent
+ *          tree where the extent item should be located at is read locked and
+ *          accessible in the given path.
+ */
+static noinline int check_committed_ref(struct btrfs_inode *inode,
 					struct btrfs_path *path,
-					u64 objectid, u64 offset, u64 bytenr,
-					bool strict)
+					u64 offset, u64 bytenr)
 {
+	struct btrfs_root *root = inode->root;
 	struct btrfs_fs_info *fs_info = root->fs_info;
 	struct btrfs_root *extent_root = btrfs_extent_root(fs_info, bytenr);
 	struct extent_buffer *leaf;
@@ -2341,35 +2353,32 @@ static noinline int check_committed_ref(struct btrfs_root *root,
 
 	ret = btrfs_search_slot(NULL, extent_root, &key, path, 0, 0);
 	if (ret < 0)
-		goto out;
+		return ret;
 	if (ret == 0) {
 		/*
 		 * Key with offset -1 found, there would have to exist an extent
 		 * item with such offset, but this is out of the valid range.
 		 */
-		ret = -EUCLEAN;
-		goto out;
+		return -EUCLEAN;
 	}
 
-	ret = -ENOENT;
 	if (path->slots[0] == 0)
-		goto out;
+		return -ENOENT;
 
 	path->slots[0]--;
 	leaf = path->nodes[0];
 	btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
 
 	if (key.objectid != bytenr || key.type != BTRFS_EXTENT_ITEM_KEY)
-		goto out;
+		return -ENOENT;
 
-	ret = 1;
 	item_size = btrfs_item_size(leaf, path->slots[0]);
 	ei = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
 	expected_size = sizeof(*ei) + btrfs_extent_inline_ref_size(BTRFS_EXTENT_DATA_REF_KEY);
 
 	/* No inline refs; we need to bail before checking for owner ref. */
 	if (item_size == sizeof(*ei))
-		goto out;
+		return 1;
 
 	/* Check for an owner ref; skip over it to the real inline refs. */
 	iref = (struct btrfs_extent_inline_ref *)(ei + 1);
@@ -2377,56 +2386,69 @@ static noinline int check_committed_ref(struct btrfs_root *root,
 	if (btrfs_fs_incompat(fs_info, SIMPLE_QUOTA) && type == BTRFS_EXTENT_OWNER_REF_KEY) {
 		expected_size += btrfs_extent_inline_ref_size(BTRFS_EXTENT_OWNER_REF_KEY);
 		iref = (struct btrfs_extent_inline_ref *)(iref + 1);
+		type = btrfs_get_extent_inline_ref_type(leaf, iref, BTRFS_REF_TYPE_DATA);
 	}
 
 	/* If extent item has more than 1 inline ref then it's shared */
 	if (item_size != expected_size)
-		goto out;
-
-	/*
-	 * If extent created before last snapshot => it's shared unless the
-	 * snapshot has been deleted. Use the heuristic if strict is false.
-	 */
-	if (!strict &&
-	    (btrfs_extent_generation(leaf, ei) <=
-	     btrfs_root_last_snapshot(&root->root_item)))
-		goto out;
+		return 1;
 
 	/* If this extent has SHARED_DATA_REF then it's shared */
-	type = btrfs_get_extent_inline_ref_type(leaf, iref, BTRFS_REF_TYPE_DATA);
 	if (type != BTRFS_EXTENT_DATA_REF_KEY)
-		goto out;
+		return 1;
 
 	ref = (struct btrfs_extent_data_ref *)(&iref->offset);
 	if (btrfs_extent_refs(leaf, ei) !=
 	    btrfs_extent_data_ref_count(leaf, ref) ||
 	    btrfs_extent_data_ref_root(leaf, ref) != btrfs_root_id(root) ||
-	    btrfs_extent_data_ref_objectid(leaf, ref) != objectid ||
+	    btrfs_extent_data_ref_objectid(leaf, ref) != btrfs_ino(inode) ||
 	    btrfs_extent_data_ref_offset(leaf, ref) != offset)
-		goto out;
+		return 1;
 
-	ret = 0;
-out:
-	return ret;
+	return 0;
 }
 
-int btrfs_cross_ref_exist(struct btrfs_root *root, u64 objectid, u64 offset,
-			  u64 bytenr, bool strict, struct btrfs_path *path)
+int btrfs_cross_ref_exist(struct btrfs_inode *inode, u64 offset,
+			  u64 bytenr, struct btrfs_path *path)
 {
 	int ret;
 
 	do {
-		ret = check_committed_ref(root, path, objectid,
-					  offset, bytenr, strict);
+		ret = check_committed_ref(inode, path, offset, bytenr);
 		if (ret && ret != -ENOENT)
 			goto out;
 
-		ret = check_delayed_ref(root, path, objectid, offset, bytenr);
+		/*
+		 * The path must have a locked leaf from the extent tree where
+		 * the extent item for our extent is located, in case it exists,
+		 * or where it should be located in case it doesn't exist yet
+		 * because it's new and its delayed ref was not yet flushed.
+		 * We need to lock the delayed ref head at check_delayed_ref(),
+		 * if one exists, while holding the leaf locked in order to not
+		 * race with delayed ref flushing, missing references and
+		 * incorrectly reporting that the extent is not shared.
+		 */
+		if (IS_ENABLED(CONFIG_BTRFS_ASSERT)) {
+			struct extent_buffer *leaf = path->nodes[0];
+
+			ASSERT(leaf != NULL);
+			btrfs_assert_tree_read_locked(leaf);
+
+			if (ret != -ENOENT) {
+				struct btrfs_key key;
+
+				btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
+				ASSERT(key.objectid == bytenr);
+				ASSERT(key.type == BTRFS_EXTENT_ITEM_KEY);
+			}
+		}
+
+		ret = check_delayed_ref(inode, path, offset, bytenr);
 	} while (ret == -EAGAIN && !path->nowait);
 
 out:
 	btrfs_release_path(path);
-	if (btrfs_is_data_reloc_root(root))
+	if (btrfs_is_data_reloc_root(inode->root))
 		WARN_ON(ret > 0);
 	return ret;
 }
@@ -2571,13 +2593,10 @@ static int pin_down_extent(struct btrfs_trans_handle *trans,
 			   struct btrfs_block_group *cache,
 			   u64 bytenr, u64 num_bytes, int reserved)
 {
-	struct btrfs_fs_info *fs_info = cache->fs_info;
-
 	spin_lock(&cache->space_info->lock);
 	spin_lock(&cache->lock);
 	cache->pinned += num_bytes;
-	btrfs_space_info_update_bytes_pinned(fs_info, cache->space_info,
-					     num_bytes);
+	btrfs_space_info_update_bytes_pinned(cache->space_info, num_bytes);
 	if (reserved) {
 		cache->reserved -= num_bytes;
 		cache->space_info->bytes_reserved -= num_bytes;
@@ -2724,15 +2743,15 @@ static int unpin_extent_range(struct btrfs_fs_info *fs_info,
 {
 	struct btrfs_block_group *cache = NULL;
 	struct btrfs_space_info *space_info;
-	struct btrfs_block_rsv *global_rsv = &fs_info->global_block_rsv;
 	struct btrfs_free_cluster *cluster = NULL;
-	u64 len;
 	u64 total_unpinned = 0;
 	u64 empty_cluster = 0;
 	bool readonly;
 	int ret = 0;
 
 	while (start <= end) {
+		u64 len;
+
 		readonly = false;
 		if (!cache ||
 		    start >= cache->start + cache->length) {
@@ -2778,37 +2797,19 @@ static int unpin_extent_range(struct btrfs_fs_info *fs_info,
 		spin_lock(&space_info->lock);
 		spin_lock(&cache->lock);
 		cache->pinned -= len;
-		btrfs_space_info_update_bytes_pinned(fs_info, space_info, -len);
+		btrfs_space_info_update_bytes_pinned(space_info, -len);
 		space_info->max_extent_size = 0;
 		if (cache->ro) {
 			space_info->bytes_readonly += len;
 			readonly = true;
 		} else if (btrfs_is_zoned(fs_info)) {
 			/* Need reset before reusing in a zoned block group */
-			btrfs_space_info_update_bytes_zone_unusable(fs_info, space_info,
-								    len);
+			btrfs_space_info_update_bytes_zone_unusable(space_info, len);
 			readonly = true;
 		}
 		spin_unlock(&cache->lock);
-		if (!readonly && return_free_space &&
-		    global_rsv->space_info == space_info) {
-			spin_lock(&global_rsv->lock);
-			if (!global_rsv->full) {
-				u64 to_add = min(len, global_rsv->size -
-						      global_rsv->reserved);
-
-				global_rsv->reserved += to_add;
-				btrfs_space_info_update_bytes_may_use(fs_info,
-						space_info, to_add);
-				if (global_rsv->reserved >= global_rsv->size)
-					global_rsv->full = 1;
-				len -= to_add;
-			}
-			spin_unlock(&global_rsv->lock);
-		}
-		/* Add to any tickets we may have */
-		if (!readonly && return_free_space && len)
-			btrfs_try_granting_tickets(fs_info, space_info);
+		if (!readonly && return_free_space)
+			btrfs_return_free_space(space_info, len);
 		spin_unlock(&space_info->lock);
 	}
 
@@ -3259,7 +3260,6 @@ static int __btrfs_free_extent(struct btrfs_trans_handle *trans,
 			}
 		} else {
 			btrfs_set_extent_refs(leaf, ei, refs);
-			btrfs_mark_buffer_dirty(trans, leaf);
 		}
 		if (found_extent) {
 			ret = remove_extent_backref(trans, extent_root, path,
@@ -4827,7 +4827,6 @@ static int alloc_reserved_file_extent(struct btrfs_trans_handle *trans,
 		btrfs_set_extent_data_ref_count(leaf, ref, ref_mod);
 	}
 
-	btrfs_mark_buffer_dirty(trans, path->nodes[0]);
 	btrfs_free_path(path);
 
 	return alloc_reserved_extent(trans, ins->objectid, ins->offset);
@@ -4902,7 +4901,6 @@ static int alloc_reserved_tree_block(struct btrfs_trans_handle *trans,
 		btrfs_set_extent_inline_ref_offset(leaf, iref, node->ref_root);
 	}
 
-	btrfs_mark_buffer_dirty(trans, leaf);
 	btrfs_free_path(path);
 
 	return alloc_reserved_extent(trans, node->bytenr, fs_info->nodesize);
diff --git a/fs/btrfs/extent-tree.h b/fs/btrfs/extent-tree.h
index 2ad5113..cfa5226 100644
--- a/fs/btrfs/extent-tree.h
+++ b/fs/btrfs/extent-tree.h
@@ -116,8 +116,7 @@ int btrfs_pin_extent(struct btrfs_trans_handle *trans, u64 bytenr, u64 num,
 int btrfs_pin_extent_for_log_replay(struct btrfs_trans_handle *trans,
 				    const struct extent_buffer *eb);
 int btrfs_exclude_logged_extents(struct extent_buffer *eb);
-int btrfs_cross_ref_exist(struct btrfs_root *root,
-			  u64 objectid, u64 offset, u64 bytenr, bool strict,
+int btrfs_cross_ref_exist(struct btrfs_inode *inode, u64 offset, u64 bytenr,
 			  struct btrfs_path *path);
 struct extent_buffer *btrfs_alloc_tree_block(struct btrfs_trans_handle *trans,
 					     struct btrfs_root *root,
@@ -163,5 +162,9 @@ int btrfs_drop_subtree(struct btrfs_trans_handle *trans,
 			struct btrfs_root *root,
 			struct extent_buffer *node,
 			struct extent_buffer *parent);
+void btrfs_error_unpin_extent_range(struct btrfs_fs_info *fs_info, u64 start, u64 end);
+int btrfs_discard_extent(struct btrfs_fs_info *fs_info, u64 bytenr,
+			 u64 num_bytes, u64 *actual_bytes);
+int btrfs_trim_fs(struct btrfs_fs_info *fs_info, struct fstrim_range *range);
 
 #endif
diff --git a/fs/btrfs/extent_io.c b/fs/btrfs/extent_io.c
index b923d0c..d9f8563 100644
--- a/fs/btrfs/extent_io.c
+++ b/fs/btrfs/extent_io.c
@@ -198,9 +198,8 @@ static void __process_folios_contig(struct address_space *mapping,
 				    u64 end, unsigned long page_ops)
 {
 	struct btrfs_fs_info *fs_info = inode_to_fs_info(mapping->host);
-	pgoff_t start_index = start >> PAGE_SHIFT;
+	pgoff_t index = start >> PAGE_SHIFT;
 	pgoff_t end_index = end >> PAGE_SHIFT;
-	pgoff_t index = start_index;
 	struct folio_batch fbatch;
 	int i;
 
@@ -221,7 +220,7 @@ static void __process_folios_contig(struct address_space *mapping,
 	}
 }
 
-static noinline void __unlock_for_delalloc(const struct inode *inode,
+static noinline void unlock_delalloc_folio(const struct inode *inode,
 					   const struct folio *locked_folio,
 					   u64 start, u64 end)
 {
@@ -242,9 +241,8 @@ static noinline int lock_delalloc_folios(struct inode *inode,
 {
 	struct btrfs_fs_info *fs_info = inode_to_fs_info(inode);
 	struct address_space *mapping = inode->i_mapping;
-	pgoff_t start_index = start >> PAGE_SHIFT;
+	pgoff_t index = start >> PAGE_SHIFT;
 	pgoff_t end_index = end >> PAGE_SHIFT;
-	pgoff_t index = start_index;
 	u64 processed_end = start;
 	struct folio_batch fbatch;
 
@@ -288,8 +286,7 @@ static noinline int lock_delalloc_folios(struct inode *inode,
 out:
 	folio_batch_release(&fbatch);
 	if (processed_end > start)
-		__unlock_for_delalloc(inode, locked_folio, start,
-				      processed_end);
+		unlock_delalloc_folio(inode, locked_folio, start, processed_end);
 	return -EAGAIN;
 }
 
@@ -390,7 +387,7 @@ noinline_for_stack bool find_lock_delalloc_range(struct inode *inode,
 
 	unlock_extent(tree, delalloc_start, delalloc_end, &cached_state);
 	if (!ret) {
-		__unlock_for_delalloc(inode, locked_folio, delalloc_start,
+		unlock_delalloc_folio(inode, locked_folio, delalloc_start,
 				      delalloc_end);
 		cond_resched();
 		goto again;
@@ -710,6 +707,7 @@ static void alloc_new_bio(struct btrfs_inode *inode,
 	bbio = btrfs_bio_alloc(BIO_MAX_VECS, bio_ctrl->opf, fs_info,
 			       bio_ctrl->end_io_func, NULL);
 	bbio->bio.bi_iter.bi_sector = disk_bytenr >> SECTOR_SHIFT;
+	bbio->bio.bi_write_hint = inode->vfs_inode.i_write_hint;
 	bbio->inode = inode;
 	bbio->file_offset = file_offset;
 	bio_ctrl->bbio = bbio;
@@ -862,11 +860,6 @@ static int attach_extent_buffer_folio(struct extent_buffer *eb,
 	return ret;
 }
 
-int set_page_extent_mapped(struct page *page)
-{
-	return set_folio_extent_mapped(page_folio(page));
-}
-
 int set_folio_extent_mapped(struct folio *folio)
 {
 	struct btrfs_fs_info *fs_info;
@@ -901,9 +894,9 @@ void clear_folio_extent_mapped(struct folio *folio)
 	folio_detach_private(folio);
 }
 
-static struct extent_map *__get_extent_map(struct inode *inode,
-					   struct folio *folio, u64 start,
-					   u64 len, struct extent_map **em_cached)
+static struct extent_map *get_extent_map(struct btrfs_inode *inode,
+					 struct folio *folio, u64 start,
+					 u64 len, struct extent_map **em_cached)
 {
 	struct extent_map *em;
 	struct extent_state *cached_state = NULL;
@@ -922,14 +915,14 @@ static struct extent_map *__get_extent_map(struct inode *inode,
 		*em_cached = NULL;
 	}
 
-	btrfs_lock_and_flush_ordered_range(BTRFS_I(inode), start, start + len - 1, &cached_state);
-	em = btrfs_get_extent(BTRFS_I(inode), folio, start, len);
+	btrfs_lock_and_flush_ordered_range(inode, start, start + len - 1, &cached_state);
+	em = btrfs_get_extent(inode, folio, start, len);
 	if (!IS_ERR(em)) {
 		BUG_ON(*em_cached);
 		refcount_inc(&em->refs);
 		*em_cached = em;
 	}
-	unlock_extent(&BTRFS_I(inode)->io_tree, start, start + len - 1, &cached_state);
+	unlock_extent(&inode->io_tree, start, start + len - 1, &cached_state);
 
 	return em;
 }
@@ -985,8 +978,7 @@ static int btrfs_do_readpage(struct folio *folio, struct extent_map **em_cached,
 			end_folio_read(folio, true, cur, iosize);
 			break;
 		}
-		em = __get_extent_map(inode, folio, cur, end - cur + 1,
-				      em_cached);
+		em = get_extent_map(BTRFS_I(inode), folio, cur, end - cur + 1, em_cached);
 		if (IS_ERR(em)) {
 			end_folio_read(folio, false, cur, end + 1 - cur);
 			return PTR_ERR(em);
@@ -1142,14 +1134,19 @@ static bool find_next_delalloc_bitmap(struct folio *folio,
 }
 
 /*
- * helper for extent_writepage(), doing all of the delayed allocation setup.
+ * Do all of the delayed allocation setup.
  *
- * This returns 1 if btrfs_run_delalloc_range function did all the work required
- * to write the page (copy into inline extent).  In this case the IO has
- * been started and the page is already unlocked.
+ * Return >0 if all the dirty blocks are submitted async (compression) or inlined.
+ * The @folio should no longer be touched (treat it as already unlocked).
  *
- * This returns 0 if all went well (page still locked)
- * This returns < 0 if there were errors (page still locked)
+ * Return 0 if there is still dirty block that needs to be submitted through
+ * extent_writepage_io().
+ * bio_ctrl->submit_bitmap will indicate which blocks of the folio should be
+ * submitted, and @folio is still kept locked.
+ *
+ * Return <0 if there is any error hit.
+ * Any allocated ordered extent range covering this folio will be marked
+ * finished (IOERR), and @folio is still kept locked.
  */
 static noinline_for_stack int writepage_delalloc(struct btrfs_inode *inode,
 						 struct folio *folio,
@@ -1167,6 +1164,16 @@ static noinline_for_stack int writepage_delalloc(struct btrfs_inode *inode,
 	 * last delalloc end.
 	 */
 	u64 last_delalloc_end = 0;
+	/*
+	 * The range end (exclusive) of the last successfully finished delalloc
+	 * range.
+	 * Any range covered by ordered extent must either be manually marked
+	 * finished (error handling), or has IO submitted (and finish the
+	 * ordered extent normally).
+	 *
+	 * This records the end of ordered extent cleanup if we hit an error.
+	 */
+	u64 last_finished_delalloc_end = page_start;
 	u64 delalloc_start = page_start;
 	u64 delalloc_end = page_end;
 	u64 delalloc_to_write = 0;
@@ -1235,11 +1242,28 @@ static noinline_for_stack int writepage_delalloc(struct btrfs_inode *inode,
 			found_len = last_delalloc_end + 1 - found_start;
 
 		if (ret >= 0) {
+			/*
+			 * Some delalloc range may be created by previous folios.
+			 * Thus we still need to clean up this range during error
+			 * handling.
+			 */
+			last_finished_delalloc_end = found_start;
 			/* No errors hit so far, run the current delalloc range. */
 			ret = btrfs_run_delalloc_range(inode, folio,
 						       found_start,
 						       found_start + found_len - 1,
 						       wbc);
+			if (ret >= 0)
+				last_finished_delalloc_end = found_start + found_len;
+			if (unlikely(ret < 0))
+				btrfs_err_rl(fs_info,
+"failed to run delalloc range, root=%lld ino=%llu folio=%llu submit_bitmap=%*pbl start=%llu len=%u: %d",
+					     btrfs_root_id(inode->root),
+					     btrfs_ino(inode),
+					     folio_pos(folio),
+					     fs_info->sectors_per_page,
+					     &bio_ctrl->submit_bitmap,
+					     found_start, found_len, ret);
 		} else {
 			/*
 			 * We've hit an error during previous delalloc range,
@@ -1247,7 +1271,7 @@ static noinline_for_stack int writepage_delalloc(struct btrfs_inode *inode,
 			 */
 			unlock_extent(&inode->io_tree, found_start,
 				      found_start + found_len - 1, NULL);
-			__unlock_for_delalloc(&inode->vfs_inode, folio,
+			unlock_delalloc_folio(&inode->vfs_inode, folio,
 					      found_start,
 					      found_start + found_len - 1);
 		}
@@ -1274,8 +1298,22 @@ static noinline_for_stack int writepage_delalloc(struct btrfs_inode *inode,
 
 		delalloc_start = found_start + found_len;
 	}
-	if (ret < 0)
+	/*
+	 * It's possible we had some ordered extents created before we hit
+	 * an error, cleanup non-async successfully created delalloc ranges.
+	 */
+	if (unlikely(ret < 0)) {
+		unsigned int bitmap_size = min(
+				(last_finished_delalloc_end - page_start) >>
+				fs_info->sectorsize_bits,
+				fs_info->sectors_per_page);
+
+		for_each_set_bit(bit, &bio_ctrl->submit_bitmap, bitmap_size)
+			btrfs_mark_ordered_io_finished(inode, folio,
+				page_start + (bit << fs_info->sectorsize_bits),
+				fs_info->sectorsize, false);
 		return ret;
+	}
 out:
 	if (last_delalloc_end)
 		delalloc_end = last_delalloc_end;
@@ -1335,7 +1373,7 @@ static int submit_one_sector(struct btrfs_inode *inode,
 
 	em = btrfs_get_extent(inode, NULL, filepos, sectorsize);
 	if (IS_ERR(em))
-		return PTR_ERR_OR_ZERO(em);
+		return PTR_ERR(em);
 
 	extent_offset = filepos - em->start;
 	em_end = extent_map_end(em);
@@ -1391,6 +1429,7 @@ static noinline_for_stack int extent_writepage_io(struct btrfs_inode *inode,
 	struct btrfs_fs_info *fs_info = inode->root->fs_info;
 	unsigned long range_bitmap = 0;
 	bool submitted_io = false;
+	bool error = false;
 	const u64 folio_start = folio_pos(folio);
 	u64 cur;
 	int bit;
@@ -1433,11 +1472,26 @@ static noinline_for_stack int extent_writepage_io(struct btrfs_inode *inode,
 			break;
 		}
 		ret = submit_one_sector(inode, folio, cur, bio_ctrl, i_size);
-		if (ret < 0)
-			goto out;
+		if (unlikely(ret < 0)) {
+			/*
+			 * bio_ctrl may contain a bio crossing several folios.
+			 * Submit it immediately so that the bio has a chance
+			 * to finish normally, other than marked as error.
+			 */
+			submit_one_bio(bio_ctrl);
+			/*
+			 * Failed to grab the extent map which should be very rare.
+			 * Since there is no bio submitted to finish the ordered
+			 * extent, we have to manually finish this sector.
+			 */
+			btrfs_mark_ordered_io_finished(inode, folio, cur,
+						       fs_info->sectorsize, false);
+			error = true;
+			continue;
+		}
 		submitted_io = true;
 	}
-out:
+
 	/*
 	 * If we didn't submitted any sector (>= i_size), folio dirty get
 	 * cleared but PAGECACHE_TAG_DIRTY is not cleared (only cleared
@@ -1445,8 +1499,11 @@ static noinline_for_stack int extent_writepage_io(struct btrfs_inode *inode,
 	 *
 	 * Here we set writeback and clear for the range. If the full folio
 	 * is no longer dirty then we clear the PAGECACHE_TAG_DIRTY tag.
+	 *
+	 * If we hit any error, the corresponding sector will still be dirty
+	 * thus no need to clear PAGECACHE_TAG_DIRTY.
 	 */
-	if (!submitted_io) {
+	if (!submitted_io && !error) {
 		btrfs_folio_set_writeback(fs_info, folio, start, len);
 		btrfs_folio_clear_writeback(fs_info, folio, start, len);
 	}
@@ -1464,15 +1521,14 @@ static noinline_for_stack int extent_writepage_io(struct btrfs_inode *inode,
  */
 static int extent_writepage(struct folio *folio, struct btrfs_bio_ctrl *bio_ctrl)
 {
-	struct inode *inode = folio->mapping->host;
-	struct btrfs_fs_info *fs_info = inode_to_fs_info(inode);
-	const u64 page_start = folio_pos(folio);
+	struct btrfs_inode *inode = BTRFS_I(folio->mapping->host);
+	struct btrfs_fs_info *fs_info = inode->root->fs_info;
 	int ret;
 	size_t pg_offset;
-	loff_t i_size = i_size_read(inode);
+	loff_t i_size = i_size_read(&inode->vfs_inode);
 	unsigned long end_index = i_size >> PAGE_SHIFT;
 
-	trace_extent_writepage(folio, inode, bio_ctrl->wbc);
+	trace_extent_writepage(folio, &inode->vfs_inode, bio_ctrl->wbc);
 
 	WARN_ON(!folio_test_locked(folio));
 
@@ -1496,26 +1552,28 @@ static int extent_writepage(struct folio *folio, struct btrfs_bio_ctrl *bio_ctrl
 	if (ret < 0)
 		goto done;
 
-	ret = writepage_delalloc(BTRFS_I(inode), folio, bio_ctrl);
+	ret = writepage_delalloc(inode, folio, bio_ctrl);
 	if (ret == 1)
 		return 0;
 	if (ret)
 		goto done;
 
-	ret = extent_writepage_io(BTRFS_I(inode), folio, folio_pos(folio),
+	ret = extent_writepage_io(inode, folio, folio_pos(folio),
 				  PAGE_SIZE, bio_ctrl, i_size);
 	if (ret == 1)
 		return 0;
+	if (ret < 0)
+		btrfs_err_rl(fs_info,
+"failed to submit blocks, root=%lld inode=%llu folio=%llu submit_bitmap=%*pbl: %d",
+			     btrfs_root_id(inode->root), btrfs_ino(inode),
+			     folio_pos(folio), fs_info->sectors_per_page,
+			     &bio_ctrl->submit_bitmap, ret);
 
 	bio_ctrl->wbc->nr_to_write--;
 
 done:
-	if (ret) {
-		btrfs_mark_ordered_io_finished(BTRFS_I(inode), folio,
-					       page_start, PAGE_SIZE, !ret);
+	if (ret < 0)
 		mapping_set_error(folio->mapping, ret);
-	}
-
 	/*
 	 * Only unlock ranges that are submitted. As there can be some async
 	 * submitted ranges inside the folio.
@@ -1525,12 +1583,6 @@ static int extent_writepage(struct folio *folio, struct btrfs_bio_ctrl *bio_ctrl
 	return ret;
 }
 
-void wait_on_extent_buffer_writeback(struct extent_buffer *eb)
-{
-	wait_on_bit_io(&eb->bflags, EXTENT_BUFFER_WRITEBACK,
-		       TASK_UNINTERRUPTIBLE);
-}
-
 /*
  * Lock extent buffer status and pages for writeback.
  *
@@ -1671,11 +1723,10 @@ static void end_bbio_meta_write(struct btrfs_bio *bbio)
 {
 	struct extent_buffer *eb = bbio->private;
 	struct btrfs_fs_info *fs_info = eb->fs_info;
-	bool uptodate = !bbio->bio.bi_status;
 	struct folio_iter fi;
 	u32 bio_offset = 0;
 
-	if (!uptodate)
+	if (bbio->bio.bi_status != BLK_STS_OK)
 		set_btree_ioerr(eb);
 
 	bio_for_each_folio_all(fi, &bbio->bio) {
@@ -2292,11 +2343,8 @@ void extent_write_locked_range(struct inode *inode, const struct folio *locked_f
 		if (ret == 1)
 			goto next_page;
 
-		if (ret) {
-			btrfs_mark_ordered_io_finished(BTRFS_I(inode), folio,
-						       cur, cur_len, !ret);
+		if (ret)
 			mapping_set_error(mapping, ret);
-		}
 		btrfs_folio_end_lock(fs_info, folio, cur, cur_len);
 		if (ret < 0)
 			found_error = true;
@@ -2495,11 +2543,6 @@ bool try_release_extent_mapping(struct folio *folio, gfp_t mask)
 	return try_release_extent_state(io_tree, folio);
 }
 
-static void __free_extent_buffer(struct extent_buffer *eb)
-{
-	kmem_cache_free(extent_buffer_cache, eb);
-}
-
 static int extent_buffer_under_io(const struct extent_buffer *eb)
 {
 	return (test_bit(EXTENT_BUFFER_WRITEBACK, &eb->bflags) ||
@@ -2580,8 +2623,8 @@ static void detach_extent_buffer_folio(const struct extent_buffer *eb, struct fo
 	spin_unlock(&folio->mapping->i_private_lock);
 }
 
-/* Release all pages attached to the extent buffer */
-static void btrfs_release_extent_buffer_pages(const struct extent_buffer *eb)
+/* Release all folios attached to the extent buffer */
+static void btrfs_release_extent_buffer_folios(const struct extent_buffer *eb)
 {
 	ASSERT(!extent_buffer_under_io(eb));
 
@@ -2603,9 +2646,9 @@ static void btrfs_release_extent_buffer_pages(const struct extent_buffer *eb)
  */
 static inline void btrfs_release_extent_buffer(struct extent_buffer *eb)
 {
-	btrfs_release_extent_buffer_pages(eb);
+	btrfs_release_extent_buffer_folios(eb);
 	btrfs_leak_debug_del_eb(eb);
-	__free_extent_buffer(eb);
+	kmem_cache_free(extent_buffer_cache, eb);
 }
 
 static struct extent_buffer *
@@ -2703,7 +2746,7 @@ struct extent_buffer *__alloc_dummy_extent_buffer(struct btrfs_fs_info *fs_info,
 			folio_put(eb->folios[i]);
 		}
 	}
-	__free_extent_buffer(eb);
+	kmem_cache_free(extent_buffer_cache, eb);
 	return NULL;
 }
 
@@ -2830,13 +2873,12 @@ struct extent_buffer *alloc_test_extent_buffer(struct btrfs_fs_info *fs_info,
 }
 #endif
 
-static struct extent_buffer *grab_extent_buffer(
-		struct btrfs_fs_info *fs_info, struct page *page)
+static struct extent_buffer *grab_extent_buffer(struct btrfs_fs_info *fs_info,
+						struct folio *folio)
 {
-	struct folio *folio = page_folio(page);
 	struct extent_buffer *exists;
 
-	lockdep_assert_held(&page->mapping->i_private_lock);
+	lockdep_assert_held(&folio->mapping->i_private_lock);
 
 	/*
 	 * For subpage case, we completely rely on radix tree to ensure we
@@ -2851,7 +2893,7 @@ static struct extent_buffer *grab_extent_buffer(
 		return NULL;
 
 	/*
-	 * We could have already allocated an eb for this page and attached one
+	 * We could have already allocated an eb for this folio and attached one
 	 * so lets see if we can get a ref on the existing eb, and if we can we
 	 * know it's good and we can just return that one, else we know we can
 	 * just overwrite folio private.
@@ -2860,16 +2902,19 @@ static struct extent_buffer *grab_extent_buffer(
 	if (atomic_inc_not_zero(&exists->refs))
 		return exists;
 
-	WARN_ON(PageDirty(page));
+	WARN_ON(folio_test_dirty(folio));
 	folio_detach_private(folio);
 	return NULL;
 }
 
-static int check_eb_alignment(struct btrfs_fs_info *fs_info, u64 start)
+/*
+ * Validate alignment constraints of eb at logical address @start.
+ */
+static bool check_eb_alignment(struct btrfs_fs_info *fs_info, u64 start)
 {
 	if (!IS_ALIGNED(start, fs_info->sectorsize)) {
 		btrfs_err(fs_info, "bad tree block start %llu", start);
-		return -EINVAL;
+		return true;
 	}
 
 	if (fs_info->nodesize < PAGE_SIZE &&
@@ -2877,14 +2922,14 @@ static int check_eb_alignment(struct btrfs_fs_info *fs_info, u64 start)
 		btrfs_err(fs_info,
 		"tree block crosses page boundary, start %llu nodesize %u",
 			  start, fs_info->nodesize);
-		return -EINVAL;
+		return true;
 	}
 	if (fs_info->nodesize >= PAGE_SIZE &&
 	    !PAGE_ALIGNED(start)) {
 		btrfs_err(fs_info,
 		"tree block is not page aligned, start %llu nodesize %u",
 			  start, fs_info->nodesize);
-		return -EINVAL;
+		return true;
 	}
 	if (!IS_ALIGNED(start, fs_info->nodesize) &&
 	    !test_and_set_bit(BTRFS_FS_UNALIGNED_TREE_BLOCK, &fs_info->flags)) {
@@ -2892,10 +2937,9 @@ static int check_eb_alignment(struct btrfs_fs_info *fs_info, u64 start)
 "tree block not nodesize aligned, start %llu nodesize %u, can be resolved by a full metadata balance",
 			      start, fs_info->nodesize);
 	}
-	return 0;
+	return false;
 }
 
-
 /*
  * Return 0 if eb->folios[i] is attached to btree inode successfully.
  * Return >0 if there is already another extent buffer for the range,
@@ -2951,8 +2995,7 @@ static int attach_eb_folio_to_filemap(struct extent_buffer *eb, int i,
 	} else if (existing_folio) {
 		struct extent_buffer *existing_eb;
 
-		existing_eb = grab_extent_buffer(fs_info,
-						 folio_page(existing_folio, 0));
+		existing_eb = grab_extent_buffer(fs_info, existing_folio);
 		if (existing_eb) {
 			/* The extent buffer still exists, we can use it directly. */
 			*found_eb_ret = existing_eb;
@@ -3149,7 +3192,7 @@ struct extent_buffer *alloc_extent_buffer(struct btrfs_fs_info *fs_info,
 	 * live buffer and won't free them prematurely.
 	 */
 	for (int i = 0; i < num_folios; i++)
-		unlock_page(folio_page(eb->folios[i], 0));
+		folio_unlock(eb->folios[i]);
 	return eb;
 
 out:
@@ -3173,7 +3216,7 @@ struct extent_buffer *alloc_extent_buffer(struct btrfs_fs_info *fs_info,
 	for (int i = 0; i < attached; i++) {
 		ASSERT(eb->folios[i]);
 		detach_extent_buffer_folio(eb, eb->folios[i]);
-		unlock_page(folio_page(eb->folios[i], 0));
+		folio_unlock(eb->folios[i]);
 		folio_put(eb->folios[i]);
 		eb->folios[i] = NULL;
 	}
@@ -3195,7 +3238,7 @@ static inline void btrfs_release_extent_buffer_rcu(struct rcu_head *head)
 	struct extent_buffer *eb =
 			container_of(head, struct extent_buffer, rcu_head);
 
-	__free_extent_buffer(eb);
+	kmem_cache_free(extent_buffer_cache, eb);
 }
 
 static int release_extent_buffer(struct extent_buffer *eb)
@@ -3219,11 +3262,11 @@ static int release_extent_buffer(struct extent_buffer *eb)
 		}
 
 		btrfs_leak_debug_del_eb(eb);
-		/* Should be safe to release our pages at this point */
-		btrfs_release_extent_buffer_pages(eb);
+		/* Should be safe to release folios at this point. */
+		btrfs_release_extent_buffer_folios(eb);
 #ifdef CONFIG_BTRFS_FS_RUN_SANITY_TESTS
 		if (unlikely(test_bit(EXTENT_BUFFER_UNMAPPED, &eb->bflags))) {
-			__free_extent_buffer(eb);
+			kmem_cache_free(extent_buffer_cache, eb);
 			return 1;
 		}
 #endif
@@ -3382,12 +3425,12 @@ void set_extent_buffer_dirty(struct extent_buffer *eb)
 		 * the above race.
 		 */
 		if (subpage)
-			lock_page(folio_page(eb->folios[0], 0));
+			folio_lock(eb->folios[0]);
 		for (int i = 0; i < num_folios; i++)
 			btrfs_folio_set_dirty(eb->fs_info, eb->folios[i],
 					      eb->start, eb->len);
 		if (subpage)
-			unlock_page(folio_page(eb->folios[0], 0));
+			folio_unlock(eb->folios[0]);
 		percpu_counter_add_batch(&eb->fs_info->dirty_metadata_bytes,
 					 eb->len,
 					 eb->fs_info->dirty_metadata_batch);
@@ -3497,8 +3540,8 @@ static void end_bbio_meta_read(struct btrfs_bio *bbio)
 	bio_put(&bbio->bio);
 }
 
-int read_extent_buffer_pages(struct extent_buffer *eb, int wait, int mirror_num,
-			     const struct btrfs_tree_parent_check *check)
+int read_extent_buffer_pages_nowait(struct extent_buffer *eb, int mirror_num,
+				    const struct btrfs_tree_parent_check *check)
 {
 	struct btrfs_bio *bbio;
 	bool ret;
@@ -3516,7 +3559,7 @@ int read_extent_buffer_pages(struct extent_buffer *eb, int wait, int mirror_num,
 
 	/* Someone else is already reading the buffer, just wait for it. */
 	if (test_and_set_bit(EXTENT_BUFFER_READING, &eb->bflags))
-		goto done;
+		return 0;
 
 	/*
 	 * Between the initial test_bit(EXTENT_BUFFER_UPTODATE) and the above
@@ -3556,14 +3599,21 @@ int read_extent_buffer_pages(struct extent_buffer *eb, int wait, int mirror_num,
 		}
 	}
 	btrfs_submit_bbio(bbio, mirror_num);
+	return 0;
+}
 
-done:
-	if (wait == WAIT_COMPLETE) {
-		wait_on_bit_io(&eb->bflags, EXTENT_BUFFER_READING, TASK_UNINTERRUPTIBLE);
-		if (!test_bit(EXTENT_BUFFER_UPTODATE, &eb->bflags))
-			return -EIO;
-	}
+int read_extent_buffer_pages(struct extent_buffer *eb, int mirror_num,
+			     const struct btrfs_tree_parent_check *check)
+{
+	int ret;
 
+	ret = read_extent_buffer_pages_nowait(eb, mirror_num, check);
+	if (ret < 0)
+		return ret;
+
+	wait_on_bit_io(&eb->bflags, EXTENT_BUFFER_READING, TASK_UNINTERRUPTIBLE);
+	if (!test_bit(EXTENT_BUFFER_UPTODATE, &eb->bflags))
+		return -EIO;
 	return 0;
 }
 
@@ -4294,7 +4344,7 @@ void btrfs_readahead_tree_block(struct btrfs_fs_info *fs_info,
 		return;
 	}
 
-	ret = read_extent_buffer_pages(eb, WAIT_NONE, 0, &check);
+	ret = read_extent_buffer_pages_nowait(eb, 0, &check);
 	if (ret < 0)
 		free_extent_buffer_stale(eb);
 	else
diff --git a/fs/btrfs/extent_io.h b/fs/btrfs/extent_io.h
index 8a36117..6c5328b 100644
--- a/fs/btrfs/extent_io.h
+++ b/fs/btrfs/extent_io.h
@@ -248,7 +248,6 @@ int btree_write_cache_pages(struct address_space *mapping,
 			    struct writeback_control *wbc);
 void btrfs_readahead(struct readahead_control *rac);
 int set_folio_extent_mapped(struct folio *folio);
-int set_page_extent_mapped(struct page *page);
 void clear_folio_extent_mapped(struct folio *folio);
 
 struct extent_buffer *alloc_extent_buffer(struct btrfs_fs_info *fs_info,
@@ -262,12 +261,17 @@ struct extent_buffer *find_extent_buffer(struct btrfs_fs_info *fs_info,
 					 u64 start);
 void free_extent_buffer(struct extent_buffer *eb);
 void free_extent_buffer_stale(struct extent_buffer *eb);
-#define WAIT_NONE	0
-#define WAIT_COMPLETE	1
-#define WAIT_PAGE_LOCK	2
-int read_extent_buffer_pages(struct extent_buffer *eb, int wait, int mirror_num,
+int read_extent_buffer_pages(struct extent_buffer *eb, int mirror_num,
 			     const struct btrfs_tree_parent_check *parent_check);
-void wait_on_extent_buffer_writeback(struct extent_buffer *eb);
+int read_extent_buffer_pages_nowait(struct extent_buffer *eb, int mirror_num,
+				    const struct btrfs_tree_parent_check *parent_check);
+
+static inline void wait_on_extent_buffer_writeback(struct extent_buffer *eb)
+{
+	wait_on_bit_io(&eb->bflags, EXTENT_BUFFER_WRITEBACK,
+		       TASK_UNINTERRUPTIBLE);
+}
+
 void btrfs_readahead_tree_block(struct btrfs_fs_info *fs_info,
 				u64 bytenr, u64 owner_root, u64 gen, int level);
 void btrfs_readahead_node_child(struct extent_buffer *node, int slot);
diff --git a/fs/btrfs/file-item.c b/fs/btrfs/file-item.c
index 886749b..d04a3b4 100644
--- a/fs/btrfs/file-item.c
+++ b/fs/btrfs/file-item.c
@@ -190,8 +190,6 @@ int btrfs_insert_hole_extent(struct btrfs_trans_handle *trans,
 	btrfs_set_file_extent_compression(leaf, item, 0);
 	btrfs_set_file_extent_encryption(leaf, item, 0);
 	btrfs_set_file_extent_other_encoding(leaf, item, 0);
-
-	btrfs_mark_buffer_dirty(trans, leaf);
 out:
 	btrfs_free_path(path);
 	return ret;
@@ -1259,7 +1257,6 @@ int btrfs_csum_file_blocks(struct btrfs_trans_handle *trans,
 	ins_size /= csum_size;
 	total_bytes += ins_size * fs_info->sectorsize;
 
-	btrfs_mark_buffer_dirty(trans, path->nodes[0]);
 	if (total_bytes < sums->len) {
 		btrfs_release_path(path);
 		cond_resched();
diff --git a/fs/btrfs/file.c b/fs/btrfs/file.c
index 14e2747..36f51c3 100644
--- a/fs/btrfs/file.c
+++ b/fs/btrfs/file.c
@@ -36,52 +36,7 @@
 #include "ioctl.h"
 #include "file.h"
 #include "super.h"
-
-/*
- * Helper to fault in page and copy.  This should go away and be replaced with
- * calls into generic code.
- */
-static noinline int btrfs_copy_from_user(loff_t pos, size_t write_bytes,
-					 struct folio *folio, struct iov_iter *i)
-{
-	size_t copied = 0;
-	size_t total_copied = 0;
-	int offset = offset_in_page(pos);
-
-	while (write_bytes > 0) {
-		size_t count = min_t(size_t, PAGE_SIZE - offset, write_bytes);
-		/*
-		 * Copy data from userspace to the current page
-		 */
-		copied = copy_folio_from_iter_atomic(folio, offset, count, i);
-
-		/* Flush processor's dcache for this page */
-		flush_dcache_folio(folio);
-
-		/*
-		 * if we get a partial write, we can end up with
-		 * partially up to date page.  These add
-		 * a lot of complexity, so make sure they don't
-		 * happen by forcing this copy to be retried.
-		 *
-		 * The rest of the btrfs_file_write code will fall
-		 * back to page at a time copies after we return 0.
-		 */
-		if (unlikely(copied < count)) {
-			if (!folio_test_uptodate(folio)) {
-				iov_iter_revert(i, copied);
-				copied = 0;
-			}
-			if (!copied)
-				break;
-		}
-
-		write_bytes -= copied;
-		total_copied += copied;
-		offset += copied;
-	}
-	return total_copied;
-}
+#include "print-tree.h"
 
 /*
  * Unlock folio after btrfs_file_write() is done with it.
@@ -106,7 +61,7 @@ static void btrfs_drop_folio(struct btrfs_fs_info *fs_info, struct folio *folio,
 }
 
 /*
- * After btrfs_copy_from_user(), update the following things for delalloc:
+ * After copy_folio_from_iter_atomic(), update the following things for delalloc:
  * - Mark newly dirtied folio as DELALLOC in the io tree.
  *   Used to advise which range is to be written back.
  * - Mark modified folio as Uptodate/Dirty and not needing COW fixup
@@ -224,7 +179,7 @@ int btrfs_drop_extents(struct btrfs_trans_handle *trans,
 	if (args->drop_cache)
 		btrfs_drop_extent_map_range(inode, args->start, args->end - 1, false);
 
-	if (args->start >= inode->disk_i_size && !args->replace_extent)
+	if (data_race(args->start >= inode->disk_i_size) && !args->replace_extent)
 		modify_tree = 0;
 
 	update_refs = (btrfs_root_id(root) != BTRFS_TREE_LOG_OBJECTID);
@@ -245,7 +200,11 @@ int btrfs_drop_extents(struct btrfs_trans_handle *trans,
 next_slot:
 		leaf = path->nodes[0];
 		if (path->slots[0] >= btrfs_header_nritems(leaf)) {
-			BUG_ON(del_nr > 0);
+			if (WARN_ON(del_nr > 0)) {
+				btrfs_print_leaf(leaf);
+				ret = -EINVAL;
+				break;
+			}
 			ret = btrfs_next_leaf(root, path);
 			if (ret < 0)
 				break;
@@ -321,7 +280,11 @@ int btrfs_drop_extents(struct btrfs_trans_handle *trans,
 		 *  | -------- extent -------- |
 		 */
 		if (args->start > key.offset && args->end < extent_end) {
-			BUG_ON(del_nr > 0);
+			if (WARN_ON(del_nr > 0)) {
+				btrfs_print_leaf(leaf);
+				ret = -EINVAL;
+				break;
+			}
 			if (extent_type == BTRFS_FILE_EXTENT_INLINE) {
 				ret = -EOPNOTSUPP;
 				break;
@@ -351,7 +314,6 @@ int btrfs_drop_extents(struct btrfs_trans_handle *trans,
 			btrfs_set_file_extent_offset(leaf, fi, extent_offset);
 			btrfs_set_file_extent_num_bytes(leaf, fi,
 							extent_end - args->start);
-			btrfs_mark_buffer_dirty(trans, leaf);
 
 			if (update_refs && disk_bytenr > 0) {
 				struct btrfs_ref ref = {
@@ -397,7 +359,6 @@ int btrfs_drop_extents(struct btrfs_trans_handle *trans,
 			btrfs_set_file_extent_offset(leaf, fi, extent_offset);
 			btrfs_set_file_extent_num_bytes(leaf, fi,
 							extent_end - args->end);
-			btrfs_mark_buffer_dirty(trans, leaf);
 			if (update_refs && disk_bytenr > 0)
 				args->bytes_found += args->end - key.offset;
 			break;
@@ -409,7 +370,11 @@ int btrfs_drop_extents(struct btrfs_trans_handle *trans,
 		 *  | -------- extent -------- |
 		 */
 		if (args->start > key.offset && args->end >= extent_end) {
-			BUG_ON(del_nr > 0);
+			if (WARN_ON(del_nr > 0)) {
+				btrfs_print_leaf(leaf);
+				ret = -EINVAL;
+				break;
+			}
 			if (extent_type == BTRFS_FILE_EXTENT_INLINE) {
 				ret = -EOPNOTSUPP;
 				break;
@@ -417,7 +382,6 @@ int btrfs_drop_extents(struct btrfs_trans_handle *trans,
 
 			btrfs_set_file_extent_num_bytes(leaf, fi,
 							args->start - key.offset);
-			btrfs_mark_buffer_dirty(trans, leaf);
 			if (update_refs && disk_bytenr > 0)
 				args->bytes_found += extent_end - args->start;
 			if (args->end == extent_end)
@@ -437,7 +401,11 @@ int btrfs_drop_extents(struct btrfs_trans_handle *trans,
 				del_slot = path->slots[0];
 				del_nr = 1;
 			} else {
-				BUG_ON(del_slot + del_nr != path->slots[0]);
+				if (WARN_ON(del_slot + del_nr != path->slots[0])) {
+					btrfs_print_leaf(leaf);
+					ret = -EINVAL;
+					break;
+				}
 				del_nr++;
 			}
 
@@ -668,7 +636,6 @@ int btrfs_mark_extent_written(struct btrfs_trans_handle *trans,
 							 trans->transid);
 			btrfs_set_file_extent_num_bytes(leaf, fi,
 							end - other_start);
-			btrfs_mark_buffer_dirty(trans, leaf);
 			goto out;
 		}
 	}
@@ -697,7 +664,6 @@ int btrfs_mark_extent_written(struct btrfs_trans_handle *trans,
 							other_end - start);
 			btrfs_set_file_extent_offset(leaf, fi,
 						     start - orig_offset);
-			btrfs_mark_buffer_dirty(trans, leaf);
 			goto out;
 		}
 	}
@@ -731,7 +697,6 @@ int btrfs_mark_extent_written(struct btrfs_trans_handle *trans,
 		btrfs_set_file_extent_offset(leaf, fi, split - orig_offset);
 		btrfs_set_file_extent_num_bytes(leaf, fi,
 						extent_end - split);
-		btrfs_mark_buffer_dirty(trans, leaf);
 
 		ref.action = BTRFS_ADD_DELAYED_REF;
 		ref.bytenr = bytenr;
@@ -810,7 +775,6 @@ int btrfs_mark_extent_written(struct btrfs_trans_handle *trans,
 		btrfs_set_file_extent_type(leaf, fi,
 					   BTRFS_FILE_EXTENT_REG);
 		btrfs_set_file_extent_generation(leaf, fi, trans->transid);
-		btrfs_mark_buffer_dirty(trans, leaf);
 	} else {
 		fi = btrfs_item_ptr(leaf, del_slot - 1,
 			   struct btrfs_file_extent_item);
@@ -819,7 +783,6 @@ int btrfs_mark_extent_written(struct btrfs_trans_handle *trans,
 		btrfs_set_file_extent_generation(leaf, fi, trans->transid);
 		btrfs_set_file_extent_num_bytes(leaf, fi,
 						extent_end - key.offset);
-		btrfs_mark_buffer_dirty(trans, leaf);
 
 		ret = btrfs_del_items(trans, root, path, del_slot, del_nr);
 		if (ret < 0) {
@@ -1052,7 +1015,7 @@ int btrfs_check_nocow_lock(struct btrfs_inode *inode, loff_t pos,
 						   &cached_state);
 	}
 	ret = can_nocow_extent(&inode->vfs_inode, lockstart, &num_bytes,
-			       NULL, nowait, false);
+			       NULL, nowait);
 	if (ret <= 0)
 		btrfs_drew_write_unlock(&root->snapshot_lock);
 	else
@@ -1252,7 +1215,23 @@ ssize_t btrfs_buffered_write(struct kiocb *iocb, struct iov_iter *i)
 			break;
 		}
 
-		copied = btrfs_copy_from_user(pos, write_bytes, folio, i);
+		copied = copy_folio_from_iter_atomic(folio,
+				offset_in_folio(folio, pos), write_bytes, i);
+		flush_dcache_folio(folio);
+
+		/*
+		 * If we get a partial write, we can end up with partially
+		 * uptodate page. Although if sector size < page size we can
+		 * handle it, but if it's not sector aligned it can cause
+		 * a lot of complexity, so make sure they don't happen by
+		 * forcing retry this copy.
+		 */
+		if (unlikely(copied < write_bytes)) {
+			if (!folio_test_uptodate(folio)) {
+				iov_iter_revert(i, copied);
+				copied = 0;
+			}
+		}
 
 		num_sectors = BTRFS_BYTES_TO_BLKS(fs_info, reserve_bytes);
 		dirty_sectors = round_up(copied + sector_offset,
@@ -2029,7 +2008,6 @@ static int fill_holes(struct btrfs_trans_handle *trans,
 		btrfs_set_file_extent_ram_bytes(leaf, fi, num_bytes);
 		btrfs_set_file_extent_offset(leaf, fi, 0);
 		btrfs_set_file_extent_generation(leaf, fi, trans->transid);
-		btrfs_mark_buffer_dirty(trans, leaf);
 		goto out;
 	}
 
@@ -2046,7 +2024,6 @@ static int fill_holes(struct btrfs_trans_handle *trans,
 		btrfs_set_file_extent_ram_bytes(leaf, fi, num_bytes);
 		btrfs_set_file_extent_offset(leaf, fi, 0);
 		btrfs_set_file_extent_generation(leaf, fi, trans->transid);
-		btrfs_mark_buffer_dirty(trans, leaf);
 		goto out;
 	}
 	btrfs_release_path(path);
@@ -2194,7 +2171,6 @@ static int btrfs_insert_replace_extent(struct btrfs_trans_handle *trans,
 	btrfs_set_file_extent_num_bytes(leaf, extent, replace_len);
 	if (extent_info->is_new_extent)
 		btrfs_set_file_extent_generation(leaf, extent, trans->transid);
-	btrfs_mark_buffer_dirty(trans, leaf);
 	btrfs_release_path(path);
 
 	ret = btrfs_inode_set_file_extent_range(inode, extent_info->file_offset,
diff --git a/fs/btrfs/free-space-cache.c b/fs/btrfs/free-space-cache.c
index cfa52ef..d42b6f8 100644
--- a/fs/btrfs/free-space-cache.c
+++ b/fs/btrfs/free-space-cache.c
@@ -12,7 +12,7 @@
 #include <linux/error-injection.h>
 #include <linux/sched/mm.h>
 #include <linux/string_choices.h>
-#include "ctree.h"
+#include "extent-tree.h"
 #include "fs.h"
 #include "messages.h"
 #include "misc.h"
@@ -198,7 +198,6 @@ static int __create_free_space_inode(struct btrfs_root *root,
 	btrfs_set_inode_nlink(leaf, inode_item, 1);
 	btrfs_set_inode_transid(leaf, inode_item, trans->transid);
 	btrfs_set_inode_block_group(leaf, inode_item, offset);
-	btrfs_mark_buffer_dirty(trans, leaf);
 	btrfs_release_path(path);
 
 	key.objectid = BTRFS_FREE_SPACE_OBJECTID;
@@ -216,7 +215,6 @@ static int __create_free_space_inode(struct btrfs_root *root,
 				struct btrfs_free_space_header);
 	memzero_extent_buffer(leaf, (unsigned long)header, sizeof(*header));
 	btrfs_set_free_space_key(leaf, header, &disk_key);
-	btrfs_mark_buffer_dirty(trans, leaf);
 	btrfs_release_path(path);
 
 	return 0;
@@ -463,7 +461,7 @@ static int io_ctl_prepare_pages(struct btrfs_io_ctl *io_ctl, bool uptodate)
 			return -ENOMEM;
 		}
 
-		ret = set_page_extent_mapped(page);
+		ret = set_folio_extent_mapped(page_folio(page));
 		if (ret < 0) {
 			unlock_page(page);
 			put_page(page);
@@ -1189,7 +1187,6 @@ update_cache_item(struct btrfs_trans_handle *trans,
 	btrfs_set_free_space_entries(leaf, header, entries);
 	btrfs_set_free_space_bitmaps(leaf, header, bitmaps);
 	btrfs_set_free_space_generation(leaf, header, trans->transid);
-	btrfs_mark_buffer_dirty(trans, leaf);
 	btrfs_release_path(path);
 
 	return 0;
diff --git a/fs/btrfs/free-space-tree.c b/fs/btrfs/free-space-tree.c
index 7ba50e1..cae540ec 100644
--- a/fs/btrfs/free-space-tree.c
+++ b/fs/btrfs/free-space-tree.c
@@ -89,7 +89,6 @@ static int add_new_free_space_info(struct btrfs_trans_handle *trans,
 			      struct btrfs_free_space_info);
 	btrfs_set_free_space_extent_count(leaf, info, 0);
 	btrfs_set_free_space_flags(leaf, info, 0);
-	btrfs_mark_buffer_dirty(trans, leaf);
 
 	ret = 0;
 out:
@@ -287,7 +286,6 @@ int convert_free_space_to_bitmaps(struct btrfs_trans_handle *trans,
 	flags |= BTRFS_FREE_SPACE_USING_BITMAPS;
 	btrfs_set_free_space_flags(leaf, info, flags);
 	expected_extent_count = btrfs_free_space_extent_count(leaf, info);
-	btrfs_mark_buffer_dirty(trans, leaf);
 	btrfs_release_path(path);
 
 	if (extent_count != expected_extent_count) {
@@ -324,7 +322,6 @@ int convert_free_space_to_bitmaps(struct btrfs_trans_handle *trans,
 		ptr = btrfs_item_ptr_offset(leaf, path->slots[0]);
 		write_extent_buffer(leaf, bitmap_cursor, ptr,
 				    data_size);
-		btrfs_mark_buffer_dirty(trans, leaf);
 		btrfs_release_path(path);
 
 		i += extent_size;
@@ -430,7 +427,6 @@ int convert_free_space_to_extents(struct btrfs_trans_handle *trans,
 	flags &= ~BTRFS_FREE_SPACE_USING_BITMAPS;
 	btrfs_set_free_space_flags(leaf, info, flags);
 	expected_extent_count = btrfs_free_space_extent_count(leaf, info);
-	btrfs_mark_buffer_dirty(trans, leaf);
 	btrfs_release_path(path);
 
 	nrbits = block_group->length >> block_group->fs_info->sectorsize_bits;
@@ -495,7 +491,6 @@ static int update_free_space_extent_count(struct btrfs_trans_handle *trans,
 
 	extent_count += new_extents;
 	btrfs_set_free_space_extent_count(path->nodes[0], info, extent_count);
-	btrfs_mark_buffer_dirty(trans, path->nodes[0]);
 	btrfs_release_path(path);
 
 	if (!(flags & BTRFS_FREE_SPACE_USING_BITMAPS) &&
@@ -1350,6 +1345,12 @@ int btrfs_rebuild_free_space_tree(struct btrfs_fs_info *fs_info)
 			btrfs_end_transaction(trans);
 			return ret;
 		}
+		if (btrfs_should_end_transaction(trans)) {
+			btrfs_end_transaction(trans);
+			trans = btrfs_start_transaction(free_space_root, 1);
+			if (IS_ERR(trans))
+				return PTR_ERR(trans);
+		}
 		node = rb_next(node);
 	}
 
diff --git a/fs/btrfs/fs.c b/fs/btrfs/fs.c
index 31c1648..09cfb43 100644
--- a/fs/btrfs/fs.c
+++ b/fs/btrfs/fs.c
@@ -4,6 +4,136 @@
 #include "ctree.h"
 #include "fs.h"
 #include "accessors.h"
+#include "volumes.h"
+
+static const struct btrfs_csums {
+	u16		size;
+	const char	name[10];
+	const char	driver[12];
+} btrfs_csums[] = {
+	[BTRFS_CSUM_TYPE_CRC32] = { .size = 4, .name = "crc32c" },
+	[BTRFS_CSUM_TYPE_XXHASH] = { .size = 8, .name = "xxhash64" },
+	[BTRFS_CSUM_TYPE_SHA256] = { .size = 32, .name = "sha256" },
+	[BTRFS_CSUM_TYPE_BLAKE2] = { .size = 32, .name = "blake2b",
+				     .driver = "blake2b-256" },
+};
+
+/* This exists for btrfs-progs usages. */
+u16 btrfs_csum_type_size(u16 type)
+{
+	return btrfs_csums[type].size;
+}
+
+int btrfs_super_csum_size(const struct btrfs_super_block *s)
+{
+	u16 t = btrfs_super_csum_type(s);
+
+	/* csum type is validated at mount time. */
+	return btrfs_csum_type_size(t);
+}
+
+const char *btrfs_super_csum_name(u16 csum_type)
+{
+	/* csum type is validated at mount time. */
+	return btrfs_csums[csum_type].name;
+}
+
+/*
+ * Return driver name if defined, otherwise the name that's also a valid driver
+ * name.
+ */
+const char *btrfs_super_csum_driver(u16 csum_type)
+{
+	/* csum type is validated at mount time */
+	return btrfs_csums[csum_type].driver[0] ?
+		btrfs_csums[csum_type].driver :
+		btrfs_csums[csum_type].name;
+}
+
+size_t __attribute_const__ btrfs_get_num_csums(void)
+{
+	return ARRAY_SIZE(btrfs_csums);
+}
+
+/*
+ * Start exclusive operation @type, return true on success.
+ */
+bool btrfs_exclop_start(struct btrfs_fs_info *fs_info,
+			enum btrfs_exclusive_operation type)
+{
+	bool ret = false;
+
+	spin_lock(&fs_info->super_lock);
+	if (fs_info->exclusive_operation == BTRFS_EXCLOP_NONE) {
+		fs_info->exclusive_operation = type;
+		ret = true;
+	}
+	spin_unlock(&fs_info->super_lock);
+
+	return ret;
+}
+
+/*
+ * Conditionally allow to enter the exclusive operation in case it's compatible
+ * with the running one.  This must be paired with btrfs_exclop_start_unlock()
+ * and btrfs_exclop_finish().
+ *
+ * Compatibility:
+ * - the same type is already running
+ * - when trying to add a device and balance has been paused
+ * - not BTRFS_EXCLOP_NONE - this is intentionally incompatible and the caller
+ *   must check the condition first that would allow none -> @type
+ */
+bool btrfs_exclop_start_try_lock(struct btrfs_fs_info *fs_info,
+				 enum btrfs_exclusive_operation type)
+{
+	spin_lock(&fs_info->super_lock);
+	if (fs_info->exclusive_operation == type ||
+	    (fs_info->exclusive_operation == BTRFS_EXCLOP_BALANCE_PAUSED &&
+	     type == BTRFS_EXCLOP_DEV_ADD))
+		return true;
+
+	spin_unlock(&fs_info->super_lock);
+	return false;
+}
+
+void btrfs_exclop_start_unlock(struct btrfs_fs_info *fs_info)
+{
+	spin_unlock(&fs_info->super_lock);
+}
+
+void btrfs_exclop_finish(struct btrfs_fs_info *fs_info)
+{
+	spin_lock(&fs_info->super_lock);
+	WRITE_ONCE(fs_info->exclusive_operation, BTRFS_EXCLOP_NONE);
+	spin_unlock(&fs_info->super_lock);
+	sysfs_notify(&fs_info->fs_devices->fsid_kobj, NULL, "exclusive_operation");
+}
+
+void btrfs_exclop_balance(struct btrfs_fs_info *fs_info,
+			  enum btrfs_exclusive_operation op)
+{
+	switch (op) {
+	case BTRFS_EXCLOP_BALANCE_PAUSED:
+		spin_lock(&fs_info->super_lock);
+		ASSERT(fs_info->exclusive_operation == BTRFS_EXCLOP_BALANCE ||
+		       fs_info->exclusive_operation == BTRFS_EXCLOP_DEV_ADD ||
+		       fs_info->exclusive_operation == BTRFS_EXCLOP_NONE ||
+		       fs_info->exclusive_operation == BTRFS_EXCLOP_BALANCE_PAUSED);
+		fs_info->exclusive_operation = BTRFS_EXCLOP_BALANCE_PAUSED;
+		spin_unlock(&fs_info->super_lock);
+		break;
+	case BTRFS_EXCLOP_BALANCE:
+		spin_lock(&fs_info->super_lock);
+		ASSERT(fs_info->exclusive_operation == BTRFS_EXCLOP_BALANCE_PAUSED);
+		fs_info->exclusive_operation = BTRFS_EXCLOP_BALANCE;
+		spin_unlock(&fs_info->super_lock);
+		break;
+	default:
+		btrfs_warn(fs_info,
+			"invalid exclop balance operation %d requested", op);
+	}
+}
 
 void __btrfs_set_fs_incompat(struct btrfs_fs_info *fs_info, u64 flag,
 			     const char *name)
diff --git a/fs/btrfs/fs.h b/fs/btrfs/fs.h
index 79a1a3d..b572d6b 100644
--- a/fs/btrfs/fs.h
+++ b/fs/btrfs/fs.h
@@ -14,10 +14,10 @@
 #include <linux/lockdep.h>
 #include <linux/spinlock.h>
 #include <linux/mutex.h>
-#include <linux/rwlock_types.h>
 #include <linux/rwsem.h>
 #include <linux/semaphore.h>
 #include <linux/list.h>
+#include <linux/pagemap.h>
 #include <linux/radix-tree.h>
 #include <linux/workqueue.h>
 #include <linux/wait.h>
@@ -627,6 +627,9 @@ struct btrfs_fs_info {
 	struct kobject *qgroups_kobj;
 	struct kobject *discard_kobj;
 
+	/* Track the number of blocks (sectors) read by the filesystem. */
+	struct percpu_counter stats_read_blocks;
+
 	/* Used to keep from writing metadata until there is a nice batch */
 	struct percpu_counter dirty_metadata_bytes;
 	struct percpu_counter delalloc_bytes;
@@ -887,6 +890,11 @@ struct btrfs_fs_info {
 #define inode_to_fs_info(_inode) (BTRFS_I(_Generic((_inode),			\
 					   struct inode *: (_inode)))->root->fs_info)
 
+static inline gfp_t btrfs_alloc_write_mask(struct address_space *mapping)
+{
+	return mapping_gfp_constraint(mapping, ~__GFP_FS);
+}
+
 static inline u64 btrfs_get_fs_generation(const struct btrfs_fs_info *fs_info)
 {
 	return READ_ONCE(fs_info->generation);
@@ -953,6 +961,8 @@ static inline u64 btrfs_calc_metadata_size(const struct btrfs_fs_info *fs_info,
 #define BTRFS_MAX_EXTENT_ITEM_SIZE(r) ((BTRFS_LEAF_DATA_SIZE(r->fs_info) >> 4) - \
 					sizeof(struct btrfs_item))
 
+#define BTRFS_BYTES_TO_BLKS(fs_info, bytes) ((bytes) >> (fs_info)->sectorsize_bits)
+
 static inline bool btrfs_is_zoned(const struct btrfs_fs_info *fs_info)
 {
 	return IS_ENABLED(CONFIG_BLK_DEV_ZONED) && fs_info->zone_size > 0;
@@ -982,6 +992,17 @@ void btrfs_exclop_balance(struct btrfs_fs_info *fs_info,
 
 int btrfs_check_ioctl_vol_args_path(const struct btrfs_ioctl_vol_args *vol_args);
 
+u16 btrfs_csum_type_size(u16 type);
+int btrfs_super_csum_size(const struct btrfs_super_block *s);
+const char *btrfs_super_csum_name(u16 csum_type);
+const char *btrfs_super_csum_driver(u16 csum_type);
+size_t __attribute_const__ btrfs_get_num_csums(void);
+
+static inline bool btrfs_is_empty_uuid(const u8 *uuid)
+{
+	return uuid_is_null((const uuid_t *)uuid);
+}
+
 /* Compatibility and incompatibility defines */
 void __btrfs_set_fs_incompat(struct btrfs_fs_info *fs_info, u64 flag,
 			     const char *name);
@@ -1058,6 +1079,14 @@ static inline void btrfs_wake_unfinished_drop(struct btrfs_fs_info *fs_info)
 	(unlikely(test_bit(BTRFS_FS_STATE_LOG_CLEANUP_ERROR,		\
 			   &(fs_info)->fs_state)))
 
+/*
+ * We use folio flag owner_2 to indicate there is an ordered extent with
+ * unfinished IO.
+ */
+#define folio_test_ordered(folio)	folio_test_owner_2(folio)
+#define folio_set_ordered(folio)	folio_set_owner_2(folio)
+#define folio_clear_ordered(folio)	folio_clear_owner_2(folio)
+
 #ifdef CONFIG_BTRFS_FS_RUN_SANITY_TESTS
 
 #define EXPORT_FOR_TESTS
diff --git a/fs/btrfs/inode-item.c b/fs/btrfs/inode-item.c
index 29572df..448aa1a 100644
--- a/fs/btrfs/inode-item.c
+++ b/fs/btrfs/inode-item.c
@@ -298,8 +298,6 @@ static int btrfs_insert_inode_extref(struct btrfs_trans_handle *trans,
 
 	ptr = (unsigned long)&extref->name;
 	write_extent_buffer(path->nodes[0], name->name, ptr, name->len);
-	btrfs_mark_buffer_dirty(trans, path->nodes[0]);
-
 out:
 	btrfs_free_path(path);
 	return ret;
@@ -363,8 +361,6 @@ int btrfs_insert_inode_ref(struct btrfs_trans_handle *trans,
 		ptr = (unsigned long)(ref + 1);
 	}
 	write_extent_buffer(path->nodes[0], name->name, ptr, name->len);
-	btrfs_mark_buffer_dirty(trans, path->nodes[0]);
-
 out:
 	btrfs_free_path(path);
 
@@ -590,7 +586,6 @@ int btrfs_truncate_inode_items(struct btrfs_trans_handle *trans,
 				num_dec = (orig_num_bytes - extent_num_bytes);
 				if (extent_start != 0)
 					control->sub_bytes += num_dec;
-				btrfs_mark_buffer_dirty(trans, leaf);
 			} else {
 				extent_num_bytes =
 					btrfs_file_extent_disk_num_bytes(leaf, fi);
diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c
index 27b2fe7..fe2c810 100644
--- a/fs/btrfs/inode.c
+++ b/fs/btrfs/inode.c
@@ -393,34 +393,13 @@ void btrfs_inode_unlock(struct btrfs_inode *inode, unsigned int ilock_flags)
  * extent (btrfs_finish_ordered_io()).
  */
 static inline void btrfs_cleanup_ordered_extents(struct btrfs_inode *inode,
-						 struct folio *locked_folio,
 						 u64 offset, u64 bytes)
 {
 	unsigned long index = offset >> PAGE_SHIFT;
 	unsigned long end_index = (offset + bytes - 1) >> PAGE_SHIFT;
-	u64 page_start = 0, page_end = 0;
 	struct folio *folio;
 
-	if (locked_folio) {
-		page_start = folio_pos(locked_folio);
-		page_end = page_start + folio_size(locked_folio) - 1;
-	}
-
 	while (index <= end_index) {
-		/*
-		 * For locked page, we will call btrfs_mark_ordered_io_finished
-		 * through btrfs_mark_ordered_io_finished() on it
-		 * in run_delalloc_range() for the error handling, which will
-		 * clear page Ordered and run the ordered extent accounting.
-		 *
-		 * Here we can't just clear the Ordered bit, or
-		 * btrfs_mark_ordered_io_finished() would skip the accounting
-		 * for the page range, and the ordered extent will never finish.
-		 */
-		if (locked_folio && index == (page_start >> PAGE_SHIFT)) {
-			index++;
-			continue;
-		}
 		folio = filemap_get_folio(inode->vfs_inode.i_mapping, index);
 		index++;
 		if (IS_ERR(folio))
@@ -436,23 +415,6 @@ static inline void btrfs_cleanup_ordered_extents(struct btrfs_inode *inode,
 		folio_put(folio);
 	}
 
-	if (locked_folio) {
-		/* The locked page covers the full range, nothing needs to be done */
-		if (bytes + offset <= page_start + folio_size(locked_folio))
-			return;
-		/*
-		 * In case this page belongs to the delalloc range being
-		 * instantiated then skip it, since the first page of a range is
-		 * going to be properly cleaned up by the caller of
-		 * run_delalloc_range
-		 */
-		if (page_start >= offset && page_end <= (offset + bytes - 1)) {
-			bytes = offset + bytes - folio_pos(locked_folio) -
-				folio_size(locked_folio);
-			offset = folio_pos(locked_folio) + folio_size(locked_folio);
-		}
-	}
-
 	return btrfs_mark_ordered_io_finished(inode, NULL, offset, bytes, false);
 }
 
@@ -564,7 +526,6 @@ static int insert_inline_extent(struct btrfs_trans_handle *trans,
 		kunmap_local(kaddr);
 		folio_put(folio);
 	}
-	btrfs_mark_buffer_dirty(trans, leaf);
 	btrfs_release_path(path);
 
 	/*
@@ -1129,19 +1090,14 @@ static void submit_uncompressed_range(struct btrfs_inode *inode,
 			       &wbc, false);
 	wbc_detach_inode(&wbc);
 	if (ret < 0) {
-		btrfs_cleanup_ordered_extents(inode, locked_folio,
-					      start, end - start + 1);
-		if (locked_folio) {
-			const u64 page_start = folio_pos(locked_folio);
-
-			folio_start_writeback(locked_folio);
-			folio_end_writeback(locked_folio);
-			btrfs_mark_ordered_io_finished(inode, locked_folio,
-						       page_start, PAGE_SIZE,
-						       !ret);
-			mapping_set_error(locked_folio->mapping, ret);
-			folio_unlock(locked_folio);
-		}
+		btrfs_cleanup_ordered_extents(inode, start, end - start + 1);
+		if (locked_folio)
+			btrfs_folio_end_lock(inode->root->fs_info, locked_folio,
+					     start, async_extent->ram_size);
+		btrfs_err_rl(inode->root->fs_info,
+			"%s failed, root=%llu inode=%llu start=%llu len=%llu: %d",
+			     __func__, btrfs_root_id(inode->root),
+			     btrfs_ino(inode), start, async_extent->ram_size, ret);
 	}
 }
 
@@ -1373,6 +1329,17 @@ static noinline int cow_file_range(struct btrfs_inode *inode,
 	alloc_hint = btrfs_get_extent_allocation_hint(inode, start, num_bytes);
 
 	/*
+	 * We're not doing compressed IO, don't unlock the first page (which
+	 * the caller expects to stay locked), don't clear any dirty bits and
+	 * don't set any writeback bits.
+	 *
+	 * Do set the Ordered (Private2) bit so we know this page was properly
+	 * setup for writepage.
+	 */
+	page_ops = (keep_locked ? 0 : PAGE_UNLOCK);
+	page_ops |= PAGE_SET_ORDERED;
+
+	/*
 	 * Relocation relies on the relocated extents to have exactly the same
 	 * size as the original extents. Normally writeback for relocation data
 	 * extents follows a NOCOW path because relocation preallocates the
@@ -1431,6 +1398,10 @@ static noinline int cow_file_range(struct btrfs_inode *inode,
 		file_extent.offset = 0;
 		file_extent.compression = BTRFS_COMPRESS_NONE;
 
+		/*
+		 * Locked range will be released either during error clean up or
+		 * after the whole range is finished.
+		 */
 		lock_extent(&inode->io_tree, start, start + cur_alloc_size - 1,
 			    &cached);
 
@@ -1476,21 +1447,6 @@ static noinline int cow_file_range(struct btrfs_inode *inode,
 
 		btrfs_dec_block_group_reservations(fs_info, ins.objectid);
 
-		/*
-		 * We're not doing compressed IO, don't unlock the first page
-		 * (which the caller expects to stay locked), don't clear any
-		 * dirty bits and don't set any writeback bits
-		 *
-		 * Do set the Ordered flag so we know this page was
-		 * properly setup for writepage.
-		 */
-		page_ops = (keep_locked ? 0 : PAGE_UNLOCK);
-		page_ops |= PAGE_SET_ORDERED;
-
-		extent_clear_unlock_delalloc(inode, start, start + cur_alloc_size - 1,
-					     locked_folio, &cached,
-					     EXTENT_LOCKED | EXTENT_DELALLOC,
-					     page_ops);
 		if (num_bytes < cur_alloc_size)
 			num_bytes = 0;
 		else
@@ -1507,6 +1463,8 @@ static noinline int cow_file_range(struct btrfs_inode *inode,
 		if (ret)
 			goto out_unlock;
 	}
+	extent_clear_unlock_delalloc(inode, orig_start, end, locked_folio, &cached,
+				     EXTENT_LOCKED | EXTENT_DELALLOC, page_ops);
 done:
 	if (done_offset)
 		*done_offset = end;
@@ -1527,35 +1485,30 @@ static noinline int cow_file_range(struct btrfs_inode *inode,
 	 * We process each region below.
 	 */
 
-	clear_bits = EXTENT_LOCKED | EXTENT_DELALLOC | EXTENT_DELALLOC_NEW |
-		EXTENT_DEFRAG | EXTENT_CLEAR_META_RESV;
-	page_ops = PAGE_UNLOCK | PAGE_START_WRITEBACK | PAGE_END_WRITEBACK;
-
 	/*
 	 * For the range (1). We have already instantiated the ordered extents
 	 * for this region. They are cleaned up by
 	 * btrfs_cleanup_ordered_extents() in e.g,
-	 * btrfs_run_delalloc_range(). EXTENT_LOCKED | EXTENT_DELALLOC are
-	 * already cleared in the above loop. And, EXTENT_DELALLOC_NEW |
-	 * EXTENT_DEFRAG | EXTENT_CLEAR_META_RESV are handled by the cleanup
-	 * function.
+	 * btrfs_run_delalloc_range().
+	 * EXTENT_DELALLOC_NEW | EXTENT_DEFRAG | EXTENT_CLEAR_META_RESV
+	 * are also handled by the cleanup function.
 	 *
-	 * However, in case of @keep_locked, we still need to unlock the pages
-	 * (except @locked_folio) to ensure all the pages are unlocked.
+	 * So here we only clear EXTENT_LOCKED and EXTENT_DELALLOC flag, and
+	 * finish the writeback of the involved folios, which will be never submitted.
 	 */
-	if (keep_locked && orig_start < start) {
+	if (orig_start < start) {
+		clear_bits = EXTENT_LOCKED | EXTENT_DELALLOC;
+		page_ops = PAGE_UNLOCK | PAGE_START_WRITEBACK | PAGE_END_WRITEBACK;
+
 		if (!locked_folio)
 			mapping_set_error(inode->vfs_inode.i_mapping, ret);
 		extent_clear_unlock_delalloc(inode, orig_start, start - 1,
-					     locked_folio, NULL, 0, page_ops);
+					     locked_folio, NULL, clear_bits, page_ops);
 	}
 
-	/*
-	 * At this point we're unlocked, we want to make sure we're only
-	 * clearing these flags under the extent lock, so lock the rest of the
-	 * range and clear everything up.
-	 */
-	lock_extent(&inode->io_tree, start, end, NULL);
+	clear_bits = EXTENT_LOCKED | EXTENT_DELALLOC | EXTENT_DELALLOC_NEW |
+		     EXTENT_DEFRAG | EXTENT_CLEAR_META_RESV;
+	page_ops = PAGE_UNLOCK | PAGE_START_WRITEBACK | PAGE_END_WRITEBACK;
 
 	/*
 	 * For the range (2). If we reserved an extent for our delalloc range
@@ -1589,6 +1542,10 @@ static noinline int cow_file_range(struct btrfs_inode *inode,
 		btrfs_qgroup_free_data(inode, NULL, start + cur_alloc_size,
 				       end - start - cur_alloc_size + 1, NULL);
 	}
+	btrfs_err_rl(fs_info,
+		     "%s failed, root=%llu inode=%llu start=%llu len=%llu: %d",
+		     __func__, btrfs_root_id(inode->root),
+		     btrfs_ino(inode), orig_start, end + 1 - orig_start, ret);
 	return ret;
 }
 
@@ -1809,7 +1766,7 @@ static int fallback_to_cow(struct btrfs_inode *inode,
 			bytes = range_bytes;
 
 		spin_lock(&sinfo->lock);
-		btrfs_space_info_update_bytes_may_use(fs_info, sinfo, bytes);
+		btrfs_space_info_update_bytes_may_use(sinfo, bytes);
 		spin_unlock(&sinfo->lock);
 
 		if (count > 0)
@@ -1837,7 +1794,6 @@ struct can_nocow_file_extent_args {
 	/* End file offset (inclusive) of the range we want to NOCOW. */
 	u64 end;
 	bool writeback_path;
-	bool strict;
 	/*
 	 * Free the path passed to can_nocow_file_extent() once it's not needed
 	 * anymore.
@@ -1892,8 +1848,7 @@ static int can_nocow_file_extent(struct btrfs_path *path,
 	 * for its subvolume was created, then this implies the extent is shared,
 	 * hence we must COW.
 	 */
-	if (!args->strict &&
-	    btrfs_file_extent_generation(leaf, fi) <=
+	if (btrfs_file_extent_generation(leaf, fi) <=
 	    btrfs_root_last_snapshot(&root->root_item))
 		goto out;
 
@@ -1922,9 +1877,8 @@ static int can_nocow_file_extent(struct btrfs_path *path,
 	 */
 	btrfs_release_path(path);
 
-	ret = btrfs_cross_ref_exist(root, btrfs_ino(inode),
-				    key->offset - args->file_extent.offset,
-				    args->file_extent.disk_bytenr, args->strict, path);
+	ret = btrfs_cross_ref_exist(inode, key->offset - args->file_extent.offset,
+				    args->file_extent.disk_bytenr, path);
 	WARN_ON_ONCE(ret > 0 && is_freespace_inode);
 	if (ret != 0)
 		goto out;
@@ -1971,6 +1925,53 @@ static int can_nocow_file_extent(struct btrfs_path *path,
 }
 
 /*
+ * Cleanup the dirty folios which will never be submitted due to error.
+ *
+ * When running a delalloc range, we may need to split the ranges (due to
+ * fragmentation or NOCOW). If we hit an error in the later part, we will error
+ * out and previously successfully executed range will never be submitted, thus
+ * we have to cleanup those folios by clearing their dirty flag, starting and
+ * finishing the writeback.
+ */
+static void cleanup_dirty_folios(struct btrfs_inode *inode,
+				 struct folio *locked_folio,
+				 u64 start, u64 end, int error)
+{
+	struct btrfs_fs_info *fs_info = inode->root->fs_info;
+	struct address_space *mapping = inode->vfs_inode.i_mapping;
+	pgoff_t start_index = start >> PAGE_SHIFT;
+	pgoff_t end_index = end >> PAGE_SHIFT;
+	u32 len;
+
+	ASSERT(end + 1 - start < U32_MAX);
+	ASSERT(IS_ALIGNED(start, fs_info->sectorsize) &&
+	       IS_ALIGNED(end + 1, fs_info->sectorsize));
+	len = end + 1 - start;
+
+	/*
+	 * Handle the locked folio first.
+	 * The btrfs_folio_clamp_*() helpers can handle range out of the folio case.
+	 */
+	btrfs_folio_clamp_finish_io(fs_info, locked_folio, start, len);
+
+	for (pgoff_t index = start_index; index <= end_index; index++) {
+		struct folio *folio;
+
+		/* Already handled at the beginning. */
+		if (index == locked_folio->index)
+			continue;
+		folio = __filemap_get_folio(mapping, index, FGP_LOCK, GFP_NOFS);
+		/* Cache already dropped, no need to do any cleanup. */
+		if (IS_ERR(folio))
+			continue;
+		btrfs_folio_clamp_finish_io(fs_info, locked_folio, start, len);
+		folio_unlock(folio);
+		folio_put(folio);
+	}
+	mapping_set_error(mapping, error);
+}
+
+/*
  * when nowcow writeback call back.  This checks for snapshots or COW copies
  * of the extents that exist in the file, and COWs the file as required.
  *
@@ -1985,6 +1986,11 @@ static noinline int run_delalloc_nocow(struct btrfs_inode *inode,
 	struct btrfs_root *root = inode->root;
 	struct btrfs_path *path;
 	u64 cow_start = (u64)-1;
+	/*
+	 * If not 0, represents the inclusive end of the last fallback_to_cow()
+	 * range. Only for error handling.
+	 */
+	u64 cow_end = 0;
 	u64 cur_offset = start;
 	int ret;
 	bool check_prev = true;
@@ -2145,6 +2151,7 @@ static noinline int run_delalloc_nocow(struct btrfs_inode *inode,
 					      found_key.offset - 1);
 			cow_start = (u64)-1;
 			if (ret) {
+				cow_end = found_key.offset - 1;
 				btrfs_dec_nocow_writers(nocow_bg);
 				goto error;
 			}
@@ -2218,11 +2225,12 @@ static noinline int run_delalloc_nocow(struct btrfs_inode *inode,
 		cow_start = cur_offset;
 
 	if (cow_start != (u64)-1) {
-		cur_offset = end;
 		ret = fallback_to_cow(inode, locked_folio, cow_start, end);
 		cow_start = (u64)-1;
-		if (ret)
+		if (ret) {
+			cow_end = end;
 			goto error;
+		}
 	}
 
 	btrfs_free_path(path);
@@ -2230,12 +2238,41 @@ static noinline int run_delalloc_nocow(struct btrfs_inode *inode,
 
 error:
 	/*
-	 * If an error happened while a COW region is outstanding, cur_offset
-	 * needs to be reset to cow_start to ensure the COW region is unlocked
-	 * as well.
+	 * There are several error cases:
+	 *
+	 * 1) Failed without falling back to COW
+	 *    start         cur_offset             end
+	 *    |/////////////|                      |
+	 *
+	 *    For range [start, cur_offset) the folios are already unlocked (except
+	 *    @locked_folio), EXTENT_DELALLOC already removed.
+	 *    Only need to clear the dirty flag as they will never be submitted.
+	 *    Ordered extent and extent maps are handled by
+	 *    btrfs_mark_ordered_io_finished() inside run_delalloc_range().
+	 *
+	 * 2) Failed with error from fallback_to_cow()
+	 *    start         cur_offset  cow_end    end
+	 *    |/////////////|-----------|          |
+	 *
+	 *    For range [start, cur_offset) it's the same as case 1).
+	 *    But for range [cur_offset, cow_end), the folios have dirty flag
+	 *    cleared and unlocked, EXTENT_DEALLLOC cleared by cow_file_range().
+	 *
+	 *    Thus we should not call extent_clear_unlock_delalloc() on range
+	 *    [cur_offset, cow_end), as the folios are already unlocked.
+	 *
+	 * So clear the folio dirty flags for [start, cur_offset) first.
 	 */
-	if (cow_start != (u64)-1)
-		cur_offset = cow_start;
+	if (cur_offset > start)
+		cleanup_dirty_folios(inode, locked_folio, start, cur_offset - 1, ret);
+
+	/*
+	 * If an error happened while a COW region is outstanding, cur_offset
+	 * needs to be reset to @cow_end + 1 to skip the COW range, as
+	 * cow_file_range() will do the proper cleanup at error.
+	 */
+	if (cow_end)
+		cur_offset = cow_end + 1;
 
 	/*
 	 * We need to lock the extent here because we're clearing DELALLOC and
@@ -2255,6 +2292,10 @@ static noinline int run_delalloc_nocow(struct btrfs_inode *inode,
 		btrfs_qgroup_free_data(inode, NULL, cur_offset, end - cur_offset + 1, NULL);
 	}
 	btrfs_free_path(path);
+	btrfs_err_rl(fs_info,
+		     "%s failed, root=%llu inode=%llu start=%llu len=%llu: %d",
+		     __func__, btrfs_root_id(inode->root),
+		     btrfs_ino(inode), start, end + 1 - start, ret);
 	return ret;
 }
 
@@ -2305,8 +2346,7 @@ int btrfs_run_delalloc_range(struct btrfs_inode *inode, struct folio *locked_fol
 
 out:
 	if (ret < 0)
-		btrfs_cleanup_ordered_extents(inode, locked_folio, start,
-					      end - start + 1);
+		btrfs_cleanup_ordered_extents(inode, start, end - start + 1);
 	return ret;
 }
 
@@ -2921,7 +2961,6 @@ static int insert_reserved_file_extent(struct btrfs_trans_handle *trans,
 			btrfs_item_ptr_offset(leaf, path->slots[0]),
 			sizeof(struct btrfs_file_extent_item));
 
-	btrfs_mark_buffer_dirty(trans, leaf);
 	btrfs_release_path(path);
 
 	/*
@@ -4085,7 +4124,6 @@ static noinline int btrfs_update_inode_item(struct btrfs_trans_handle *trans,
 				    struct btrfs_inode_item);
 
 	fill_inode_item(trans, leaf, inode_item, &inode->vfs_inode);
-	btrfs_mark_buffer_dirty(trans, leaf);
 	btrfs_set_inode_last_trans(trans, inode);
 	ret = 0;
 failed:
@@ -6380,7 +6418,6 @@ int btrfs_create_new_inode(struct btrfs_trans_handle *trans,
 		}
 	}
 
-	btrfs_mark_buffer_dirty(trans, path->nodes[0]);
 	/*
 	 * We don't need the path anymore, plus inheriting properties, adding
 	 * ACLs, security xattrs, orphan item or adding the link, will result in
@@ -7011,8 +7048,6 @@ static bool btrfs_extent_readonly(struct btrfs_fs_info *fs_info, u64 bytenr)
  * @orig_start:	(optional) Return the original file offset of the file extent
  * @orig_len:	(optional) Return the original on-disk length of the file extent
  * @ram_bytes:	(optional) Return the ram_bytes of the file extent
- * @strict:	if true, omit optimizations that might force us into unnecessary
- *		cow. e.g., don't trust generation number.
  *
  * Return:
  * >0	and update @len if we can do nocow write
@@ -7024,7 +7059,7 @@ static bool btrfs_extent_readonly(struct btrfs_fs_info *fs_info, u64 bytenr)
  */
 noinline int can_nocow_extent(struct inode *inode, u64 offset, u64 *len,
 			      struct btrfs_file_extent *file_extent,
-			      bool nowait, bool strict)
+			      bool nowait)
 {
 	struct btrfs_fs_info *fs_info = inode_to_fs_info(inode);
 	struct can_nocow_file_extent_args nocow_args = { 0 };
@@ -7077,7 +7112,6 @@ noinline int can_nocow_extent(struct inode *inode, u64 offset, u64 *len,
 
 	nocow_args.start = offset;
 	nocow_args.end = offset + *len - 1;
-	nocow_args.strict = strict;
 	nocow_args.free_path = true;
 
 	ret = can_nocow_file_extent(path, &key, BTRFS_I(inode), &nocow_args);
@@ -8027,31 +8061,45 @@ static int btrfs_rename_exchange(struct inode *old_dir,
 	/* src is a subvolume */
 	if (old_ino == BTRFS_FIRST_FREE_OBJECTID) {
 		ret = btrfs_unlink_subvol(trans, BTRFS_I(old_dir), old_dentry);
+		if (ret) {
+			btrfs_abort_transaction(trans, ret);
+			goto out_fail;
+		}
 	} else { /* src is an inode */
 		ret = __btrfs_unlink_inode(trans, BTRFS_I(old_dir),
 					   BTRFS_I(old_dentry->d_inode),
 					   old_name, &old_rename_ctx);
-		if (!ret)
-			ret = btrfs_update_inode(trans, BTRFS_I(old_inode));
-	}
-	if (ret) {
-		btrfs_abort_transaction(trans, ret);
-		goto out_fail;
+		if (ret) {
+			btrfs_abort_transaction(trans, ret);
+			goto out_fail;
+		}
+		ret = btrfs_update_inode(trans, BTRFS_I(old_inode));
+		if (ret) {
+			btrfs_abort_transaction(trans, ret);
+			goto out_fail;
+		}
 	}
 
 	/* dest is a subvolume */
 	if (new_ino == BTRFS_FIRST_FREE_OBJECTID) {
 		ret = btrfs_unlink_subvol(trans, BTRFS_I(new_dir), new_dentry);
+		if (ret) {
+			btrfs_abort_transaction(trans, ret);
+			goto out_fail;
+		}
 	} else { /* dest is an inode */
 		ret = __btrfs_unlink_inode(trans, BTRFS_I(new_dir),
 					   BTRFS_I(new_dentry->d_inode),
 					   new_name, &new_rename_ctx);
-		if (!ret)
-			ret = btrfs_update_inode(trans, BTRFS_I(new_inode));
-	}
-	if (ret) {
-		btrfs_abort_transaction(trans, ret);
-		goto out_fail;
+		if (ret) {
+			btrfs_abort_transaction(trans, ret);
+			goto out_fail;
+		}
+		ret = btrfs_update_inode(trans, BTRFS_I(new_inode));
+		if (ret) {
+			btrfs_abort_transaction(trans, ret);
+			goto out_fail;
+		}
 	}
 
 	ret = btrfs_add_link(trans, BTRFS_I(new_dir), BTRFS_I(old_inode),
@@ -8287,16 +8335,23 @@ static int btrfs_rename(struct mnt_idmap *idmap,
 
 	if (unlikely(old_ino == BTRFS_FIRST_FREE_OBJECTID)) {
 		ret = btrfs_unlink_subvol(trans, BTRFS_I(old_dir), old_dentry);
+		if (ret) {
+			btrfs_abort_transaction(trans, ret);
+			goto out_fail;
+		}
 	} else {
 		ret = __btrfs_unlink_inode(trans, BTRFS_I(old_dir),
 					   BTRFS_I(d_inode(old_dentry)),
 					   &old_fname.disk_name, &rename_ctx);
-		if (!ret)
-			ret = btrfs_update_inode(trans, BTRFS_I(old_inode));
-	}
-	if (ret) {
-		btrfs_abort_transaction(trans, ret);
-		goto out_fail;
+		if (ret) {
+			btrfs_abort_transaction(trans, ret);
+			goto out_fail;
+		}
+		ret = btrfs_update_inode(trans, BTRFS_I(old_inode));
+		if (ret) {
+			btrfs_abort_transaction(trans, ret);
+			goto out_fail;
+		}
 	}
 
 	if (new_inode) {
@@ -8304,18 +8359,27 @@ static int btrfs_rename(struct mnt_idmap *idmap,
 		if (unlikely(btrfs_ino(BTRFS_I(new_inode)) ==
 			     BTRFS_EMPTY_SUBVOL_DIR_OBJECTID)) {
 			ret = btrfs_unlink_subvol(trans, BTRFS_I(new_dir), new_dentry);
+			if (ret) {
+				btrfs_abort_transaction(trans, ret);
+				goto out_fail;
+			}
 			BUG_ON(new_inode->i_nlink == 0);
 		} else {
 			ret = btrfs_unlink_inode(trans, BTRFS_I(new_dir),
 						 BTRFS_I(d_inode(new_dentry)),
 						 &new_fname.disk_name);
+			if (ret) {
+				btrfs_abort_transaction(trans, ret);
+				goto out_fail;
+			}
 		}
-		if (!ret && new_inode->i_nlink == 0)
+		if (new_inode->i_nlink == 0) {
 			ret = btrfs_orphan_add(trans,
 					BTRFS_I(d_inode(new_dentry)));
-		if (ret) {
-			btrfs_abort_transaction(trans, ret);
-			goto out_fail;
+			if (ret) {
+				btrfs_abort_transaction(trans, ret);
+				goto out_fail;
+			}
 		}
 	}
 
@@ -8655,7 +8719,6 @@ static int btrfs_symlink(struct mnt_idmap *idmap, struct inode *dir,
 
 	ptr = btrfs_file_extent_inline_start(ei);
 	write_extent_buffer(leaf, symname, ptr, name_len);
-	btrfs_mark_buffer_dirty(trans, leaf);
 	btrfs_free_path(path);
 
 	d_instantiate_new(dentry, inode);
diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c
index 4d9305f..ae98269 100644
--- a/fs/btrfs/ioctl.c
+++ b/fs/btrfs/ioctl.c
@@ -403,86 +403,6 @@ int btrfs_fileattr_set(struct mnt_idmap *idmap,
 	return ret;
 }
 
-/*
- * Start exclusive operation @type, return true on success
- */
-bool btrfs_exclop_start(struct btrfs_fs_info *fs_info,
-			enum btrfs_exclusive_operation type)
-{
-	bool ret = false;
-
-	spin_lock(&fs_info->super_lock);
-	if (fs_info->exclusive_operation == BTRFS_EXCLOP_NONE) {
-		fs_info->exclusive_operation = type;
-		ret = true;
-	}
-	spin_unlock(&fs_info->super_lock);
-
-	return ret;
-}
-
-/*
- * Conditionally allow to enter the exclusive operation in case it's compatible
- * with the running one.  This must be paired with btrfs_exclop_start_unlock and
- * btrfs_exclop_finish.
- *
- * Compatibility:
- * - the same type is already running
- * - when trying to add a device and balance has been paused
- * - not BTRFS_EXCLOP_NONE - this is intentionally incompatible and the caller
- *   must check the condition first that would allow none -> @type
- */
-bool btrfs_exclop_start_try_lock(struct btrfs_fs_info *fs_info,
-				 enum btrfs_exclusive_operation type)
-{
-	spin_lock(&fs_info->super_lock);
-	if (fs_info->exclusive_operation == type ||
-	    (fs_info->exclusive_operation == BTRFS_EXCLOP_BALANCE_PAUSED &&
-	     type == BTRFS_EXCLOP_DEV_ADD))
-		return true;
-
-	spin_unlock(&fs_info->super_lock);
-	return false;
-}
-
-void btrfs_exclop_start_unlock(struct btrfs_fs_info *fs_info)
-{
-	spin_unlock(&fs_info->super_lock);
-}
-
-void btrfs_exclop_finish(struct btrfs_fs_info *fs_info)
-{
-	spin_lock(&fs_info->super_lock);
-	WRITE_ONCE(fs_info->exclusive_operation, BTRFS_EXCLOP_NONE);
-	spin_unlock(&fs_info->super_lock);
-	sysfs_notify(&fs_info->fs_devices->fsid_kobj, NULL, "exclusive_operation");
-}
-
-void btrfs_exclop_balance(struct btrfs_fs_info *fs_info,
-			  enum btrfs_exclusive_operation op)
-{
-	switch (op) {
-	case BTRFS_EXCLOP_BALANCE_PAUSED:
-		spin_lock(&fs_info->super_lock);
-		ASSERT(fs_info->exclusive_operation == BTRFS_EXCLOP_BALANCE ||
-		       fs_info->exclusive_operation == BTRFS_EXCLOP_DEV_ADD ||
-		       fs_info->exclusive_operation == BTRFS_EXCLOP_NONE ||
-		       fs_info->exclusive_operation == BTRFS_EXCLOP_BALANCE_PAUSED);
-		fs_info->exclusive_operation = BTRFS_EXCLOP_BALANCE_PAUSED;
-		spin_unlock(&fs_info->super_lock);
-		break;
-	case BTRFS_EXCLOP_BALANCE:
-		spin_lock(&fs_info->super_lock);
-		ASSERT(fs_info->exclusive_operation == BTRFS_EXCLOP_BALANCE_PAUSED);
-		fs_info->exclusive_operation = BTRFS_EXCLOP_BALANCE;
-		spin_unlock(&fs_info->super_lock);
-		break;
-	default:
-		btrfs_warn(fs_info,
-			"invalid exclop balance operation %d requested", op);
-	}
-}
-
 static int btrfs_ioctl_getversion(struct inode *inode, int __user *arg)
 {
 	return put_user(inode->i_generation, arg);
@@ -551,17 +471,6 @@ static noinline int btrfs_ioctl_fitrim(struct btrfs_fs_info *fs_info,
 	return ret;
 }
 
-int __pure btrfs_is_empty_uuid(const u8 *uuid)
-{
-	int i;
-
-	for (i = 0; i < BTRFS_UUID_SIZE; i++) {
-		if (uuid[i])
-			return 0;
-	}
-	return 1;
-}
-
 /*
  * Calculate the number of transaction items to reserve for creating a subvolume
  * or snapshot, not including the inode, directory entries, or parent directory.
@@ -3007,7 +2916,6 @@ static long btrfs_ioctl_default_subvol(struct file *file, void __user *argp)
 
 	btrfs_cpu_key_to_disk(&disk_key, &new_root->root_key);
 	btrfs_set_dir_item_key(path->nodes[0], di, &disk_key);
-	btrfs_mark_buffer_dirty(trans, path->nodes[0]);
 	btrfs_release_path(path);
 
 	btrfs_set_fs_incompat(fs_info, DEFAULT_SUBVOL);
@@ -5028,6 +4936,128 @@ static int btrfs_uring_encoded_read(struct io_uring_cmd *cmd, unsigned int issue
 	return ret;
 }
 
+static int btrfs_uring_encoded_write(struct io_uring_cmd *cmd, unsigned int issue_flags)
+{
+	loff_t pos;
+	struct kiocb kiocb;
+	struct file *file;
+	ssize_t ret;
+	void __user *sqe_addr;
+	struct btrfs_uring_encoded_data *data = io_uring_cmd_get_async_data(cmd)->op_data;
+
+	if (!capable(CAP_SYS_ADMIN)) {
+		ret = -EPERM;
+		goto out_acct;
+	}
+
+	file = cmd->file;
+	sqe_addr = u64_to_user_ptr(READ_ONCE(cmd->sqe->addr));
+
+	if (!(file->f_mode & FMODE_WRITE)) {
+		ret = -EBADF;
+		goto out_acct;
+	}
+
+	if (!data) {
+		data = kzalloc(sizeof(*data), GFP_NOFS);
+		if (!data) {
+			ret = -ENOMEM;
+			goto out_acct;
+		}
+
+		io_uring_cmd_get_async_data(cmd)->op_data = data;
+
+		if (issue_flags & IO_URING_F_COMPAT) {
+#if defined(CONFIG_64BIT) && defined(CONFIG_COMPAT)
+			struct btrfs_ioctl_encoded_io_args_32 args32;
+
+			if (copy_from_user(&args32, sqe_addr, sizeof(args32))) {
+				ret = -EFAULT;
+				goto out_acct;
+			}
+			data->args.iov = compat_ptr(args32.iov);
+			data->args.iovcnt = args32.iovcnt;
+			data->args.offset = args32.offset;
+			data->args.flags = args32.flags;
+			data->args.len = args32.len;
+			data->args.unencoded_len = args32.unencoded_len;
+			data->args.unencoded_offset = args32.unencoded_offset;
+			data->args.compression = args32.compression;
+			data->args.encryption = args32.encryption;
+			memcpy(data->args.reserved, args32.reserved,
+			       sizeof(data->args.reserved));
+#else
+			ret = -ENOTTY;
+			goto out_acct;
+#endif
+		} else {
+			if (copy_from_user(&data->args, sqe_addr, sizeof(data->args))) {
+				ret = -EFAULT;
+				goto out_acct;
+			}
+		}
+
+		ret = -EINVAL;
+		if (data->args.flags != 0)
+			goto out_acct;
+		if (memchr_inv(data->args.reserved, 0, sizeof(data->args.reserved)))
+			goto out_acct;
+		if (data->args.compression == BTRFS_ENCODED_IO_COMPRESSION_NONE &&
+		    data->args.encryption == BTRFS_ENCODED_IO_ENCRYPTION_NONE)
+			goto out_acct;
+		if (data->args.compression >= BTRFS_ENCODED_IO_COMPRESSION_TYPES ||
+		    data->args.encryption >= BTRFS_ENCODED_IO_ENCRYPTION_TYPES)
+			goto out_acct;
+		if (data->args.unencoded_offset > data->args.unencoded_len)
+			goto out_acct;
+		if (data->args.len > data->args.unencoded_len - data->args.unencoded_offset)
+			goto out_acct;
+
+		data->iov = data->iovstack;
+		ret = import_iovec(ITER_SOURCE, data->args.iov, data->args.iovcnt,
+				   ARRAY_SIZE(data->iovstack), &data->iov,
+				   &data->iter);
+		if (ret < 0)
+			goto out_acct;
+
+		if (iov_iter_count(&data->iter) == 0) {
+			ret = 0;
+			goto out_iov;
+		}
+	}
+
+	if (issue_flags & IO_URING_F_NONBLOCK) {
+		ret = -EAGAIN;
+		goto out_acct;
+	}
+
+	pos = data->args.offset;
+	ret = rw_verify_area(WRITE, file, &pos, data->args.len);
+	if (ret < 0)
+		goto out_iov;
+
+	init_sync_kiocb(&kiocb, file);
+	ret = kiocb_set_rw_flags(&kiocb, 0, WRITE);
+	if (ret)
+		goto out_iov;
+	kiocb.ki_pos = pos;
+
+	file_start_write(file);
+
+	ret = btrfs_do_write_iter(&kiocb, &data->iter, &data->args);
+	if (ret > 0)
+		fsnotify_modify(file);
+
+	file_end_write(file);
+out_iov:
+	kfree(data->iov);
+out_acct:
+	if (ret > 0)
+		add_wchar(current, ret);
+	inc_syscw(current);
+	return ret;
+}
+
 int btrfs_uring_cmd(struct io_uring_cmd *cmd, unsigned int issue_flags)
 {
 	switch (cmd->cmd_op) {
@@ -5036,6 +5066,12 @@ int btrfs_uring_cmd(struct io_uring_cmd *cmd, unsigned int issue_flags)
 	case BTRFS_IOC_ENCODED_READ_32:
 #endif
 		return btrfs_uring_encoded_read(cmd, issue_flags);
+
+	case BTRFS_IOC_ENCODED_WRITE:
+#if defined(CONFIG_64BIT) && defined(CONFIG_COMPAT)
+	case BTRFS_IOC_ENCODED_WRITE_32:
+#endif
+		return btrfs_uring_encoded_write(cmd, issue_flags);
 	}
 
 	return -EINVAL;
@@ -5308,6 +5344,8 @@ long btrfs_ioctl(struct file *file, unsigned int
 		return fsverity_ioctl_enable(file, (const void __user *)argp);
 	case FS_IOC_MEASURE_VERITY:
 		return fsverity_ioctl_measure(file, argp);
+	case FS_IOC_READ_VERITY_METADATA:
+		return fsverity_ioctl_read_metadata(file, argp);
 	case BTRFS_IOC_ENCODED_READ:
 		return btrfs_ioctl_encoded_read(file, argp, false);
 	case BTRFS_IOC_ENCODED_WRITE:
diff --git a/fs/btrfs/ioctl.h b/fs/btrfs/ioctl.h
index 2b760c8..ce915fc 100644
--- a/fs/btrfs/ioctl.h
+++ b/fs/btrfs/ioctl.h
@@ -19,7 +19,6 @@ int btrfs_fileattr_set(struct mnt_idmap *idmap,
 		       struct dentry *dentry, struct fileattr *fa);
 int btrfs_ioctl_get_supported_features(void __user *arg);
 void btrfs_sync_inode_flags_to_i_flags(struct inode *inode);
-int __pure btrfs_is_empty_uuid(const u8 *uuid);
 void btrfs_update_ioctl_balance_args(struct btrfs_fs_info *fs_info,
 				     struct btrfs_ioctl_balance_args *bargs);
 int btrfs_uring_cmd(struct io_uring_cmd *cmd, unsigned int issue_flags);
diff --git a/fs/btrfs/locking.h b/fs/btrfs/locking.h
index 35036b1..c69e57f 100644
--- a/fs/btrfs/locking.h
+++ b/fs/btrfs/locking.h
@@ -199,8 +199,13 @@ static inline void btrfs_assert_tree_write_locked(struct extent_buffer *eb)
 {
 	lockdep_assert_held_write(&eb->lock);
 }
+static inline void btrfs_assert_tree_read_locked(struct extent_buffer *eb)
+{
+	lockdep_assert_held_read(&eb->lock);
+}
 #else
 static inline void btrfs_assert_tree_write_locked(struct extent_buffer *eb) { }
+static inline void btrfs_assert_tree_read_locked(struct extent_buffer *eb) { }
 #endif
 
 void btrfs_unlock_up_safe(struct btrfs_path *path, int level);
diff --git a/fs/btrfs/ordered-data.c b/fs/btrfs/ordered-data.c
index 30eceaf..4aca747 100644
--- a/fs/btrfs/ordered-data.c
+++ b/fs/btrfs/ordered-data.c
@@ -1229,6 +1229,18 @@ struct btrfs_ordered_extent *btrfs_split_ordered_extent(
 	 */
 	if (WARN_ON_ONCE(len >= ordered->num_bytes))
 		return ERR_PTR(-EINVAL);
+	/*
+	 * If our ordered extent had an error there's no point in continuing.
+	 * The error may have come from a transaction abort done either by this
+	 * task or some other concurrent task, and the transaction abort path
+	 * iterates over all existing ordered extents and sets the flag
+	 * BTRFS_ORDERED_IOERR on them.
+	 */
+	if (unlikely(flags & (1U << BTRFS_ORDERED_IOERR))) {
+		const int fs_error = BTRFS_FS_ERROR(fs_info);
+
+		return fs_error ? ERR_PTR(fs_error) : ERR_PTR(-EIO);
+	}
 	/* We cannot split partially completed ordered extents. */
 	if (ordered->bytes_left) {
 		ASSERT(!(flags & ~BTRFS_ORDERED_TYPE_FLAGS));
diff --git a/fs/btrfs/qgroup.c b/fs/btrfs/qgroup.c
index f9b2149..f9d3766 100644
--- a/fs/btrfs/qgroup.c
+++ b/fs/btrfs/qgroup.c
@@ -673,9 +673,6 @@ static int add_qgroup_relation_item(struct btrfs_trans_handle *trans, u64 src,
 	key.offset = dst;
 
 	ret = btrfs_insert_empty_item(trans, quota_root, path, &key, 0);
-
-	btrfs_mark_buffer_dirty(trans, path->nodes[0]);
-
 	btrfs_free_path(path);
 	return ret;
 }
@@ -752,8 +749,6 @@ static int add_qgroup_item(struct btrfs_trans_handle *trans,
 	btrfs_set_qgroup_info_excl(leaf, qgroup_info, 0);
 	btrfs_set_qgroup_info_excl_cmpr(leaf, qgroup_info, 0);
 
-	btrfs_mark_buffer_dirty(trans, leaf);
-
 	btrfs_release_path(path);
 
 	key.type = BTRFS_QGROUP_LIMIT_KEY;
@@ -771,8 +766,6 @@ static int add_qgroup_item(struct btrfs_trans_handle *trans,
 	btrfs_set_qgroup_limit_rsv_rfer(leaf, qgroup_limit, 0);
 	btrfs_set_qgroup_limit_rsv_excl(leaf, qgroup_limit, 0);
 
-	btrfs_mark_buffer_dirty(trans, leaf);
-
 	ret = 0;
 out:
 	btrfs_free_path(path);
@@ -859,9 +852,6 @@ static int update_qgroup_limit_item(struct btrfs_trans_handle *trans,
 	btrfs_set_qgroup_limit_max_excl(l, qgroup_limit, qgroup->max_excl);
 	btrfs_set_qgroup_limit_rsv_rfer(l, qgroup_limit, qgroup->rsv_rfer);
 	btrfs_set_qgroup_limit_rsv_excl(l, qgroup_limit, qgroup->rsv_excl);
-
-	btrfs_mark_buffer_dirty(trans, l);
-
 out:
 	btrfs_free_path(path);
 	return ret;
@@ -905,9 +895,6 @@ static int update_qgroup_info_item(struct btrfs_trans_handle *trans,
 	btrfs_set_qgroup_info_rfer_cmpr(l, qgroup_info, qgroup->rfer_cmpr);
 	btrfs_set_qgroup_info_excl(l, qgroup_info, qgroup->excl);
 	btrfs_set_qgroup_info_excl_cmpr(l, qgroup_info, qgroup->excl_cmpr);
-
-	btrfs_mark_buffer_dirty(trans, l);
-
 out:
 	btrfs_free_path(path);
 	return ret;
@@ -947,9 +934,6 @@ static int update_qgroup_status_item(struct btrfs_trans_handle *trans)
 	btrfs_set_qgroup_status_generation(l, ptr, trans->transid);
 	btrfs_set_qgroup_status_rescan(l, ptr,
 				fs_info->qgroup_rescan_progress.objectid);
-
-	btrfs_mark_buffer_dirty(trans, l);
-
 out:
 	btrfs_free_path(path);
 	return ret;
@@ -1130,8 +1114,6 @@ int btrfs_quota_enable(struct btrfs_fs_info *fs_info,
 				      BTRFS_QGROUP_STATUS_FLAGS_MASK);
 	btrfs_set_qgroup_status_rescan(leaf, ptr, 0);
 
-	btrfs_mark_buffer_dirty(trans, leaf);
-
 	key.objectid = 0;
 	key.type = BTRFS_ROOT_REF_KEY;
 	key.offset = 0;
@@ -1838,9 +1820,19 @@ int btrfs_remove_qgroup(struct btrfs_trans_handle *trans, u64 qgroupid)
 	 * Thus its reserved space should all be zero, no matter if qgroup
 	 * is consistent or the mode.
 	 */
-	WARN_ON(qgroup->rsv.values[BTRFS_QGROUP_RSV_DATA] ||
-		qgroup->rsv.values[BTRFS_QGROUP_RSV_META_PREALLOC] ||
-		qgroup->rsv.values[BTRFS_QGROUP_RSV_META_PERTRANS]);
+	if (qgroup->rsv.values[BTRFS_QGROUP_RSV_DATA] ||
+	    qgroup->rsv.values[BTRFS_QGROUP_RSV_META_PREALLOC] ||
+	    qgroup->rsv.values[BTRFS_QGROUP_RSV_META_PERTRANS]) {
+		WARN_ON(IS_ENABLED(CONFIG_BTRFS_DEBUG));
+		btrfs_warn_rl(fs_info,
+"to be deleted qgroup %u/%llu has non-zero numbers, data %llu meta prealloc %llu meta pertrans %llu",
+			      btrfs_qgroup_level(qgroup->qgroupid),
+			      btrfs_qgroup_subvolid(qgroup->qgroupid),
+			      qgroup->rsv.values[BTRFS_QGROUP_RSV_DATA],
+			      qgroup->rsv.values[BTRFS_QGROUP_RSV_META_PREALLOC],
+			      qgroup->rsv.values[BTRFS_QGROUP_RSV_META_PERTRANS]);
+
+	}
 	/*
 	 * The same for rfer/excl numbers, but that's only if our qgroup is
 	 * consistent and if it's in regular qgroup mode.
@@ -1849,8 +1841,9 @@ int btrfs_remove_qgroup(struct btrfs_trans_handle *trans, u64 qgroupid)
 	 */
 	if (btrfs_qgroup_mode(fs_info) == BTRFS_QGROUP_MODE_FULL &&
 	    !(fs_info->qgroup_flags & BTRFS_QGROUP_STATUS_FLAG_INCONSISTENT)) {
-		if (WARN_ON(qgroup->rfer || qgroup->excl ||
-			    qgroup->rfer_cmpr || qgroup->excl_cmpr)) {
+		if (qgroup->rfer || qgroup->excl ||
+		    qgroup->rfer_cmpr || qgroup->excl_cmpr) {
+			WARN_ON(IS_ENABLED(CONFIG_BTRFS_DEBUG));
 			btrfs_warn_rl(fs_info,
 "to be deleted qgroup %u/%llu has non-zero numbers, rfer %llu rfer_cmpr %llu excl %llu excl_cmpr %llu",
 				      btrfs_qgroup_level(qgroup->qgroupid),
@@ -1887,11 +1880,7 @@ int btrfs_qgroup_cleanup_dropped_subvolume(struct btrfs_fs_info *fs_info, u64 su
 	 * Commit current transaction to make sure all the rfer/excl numbers
 	 * get updated.
 	 */
-	trans = btrfs_start_transaction(fs_info->quota_root, 0);
-	if (IS_ERR(trans))
-		return PTR_ERR(trans);
-
-	ret = btrfs_commit_transaction(trans);
+	ret = btrfs_commit_current_transaction(fs_info->quota_root);
 	if (ret < 0)
 		return ret;
 
@@ -1904,8 +1893,11 @@ int btrfs_qgroup_cleanup_dropped_subvolume(struct btrfs_fs_info *fs_info, u64 su
 	/*
 	 * It's squota and the subvolume still has numbers needed for future
 	 * accounting, in this case we can not delete it.  Just skip it.
+	 *
+	 * Or the qgroup is already removed by a qgroup rescan. For both cases we're
+	 * safe to ignore them.
 	 */
-	if (ret == -EBUSY)
+	if (ret == -EBUSY || ret == -ENOENT)
 		ret = 0;
 	return ret;
 }
diff --git a/fs/btrfs/raid-stripe-tree.c b/fs/btrfs/raid-stripe-tree.c
index 9ffc79f..1834011 100644
--- a/fs/btrfs/raid-stripe-tree.c
+++ b/fs/btrfs/raid-stripe-tree.c
@@ -13,12 +13,13 @@
 #include "volumes.h"
 #include "print-tree.h"
 
-static void btrfs_partially_delete_raid_extent(struct btrfs_trans_handle *trans,
+static int btrfs_partially_delete_raid_extent(struct btrfs_trans_handle *trans,
 					       struct btrfs_path *path,
 					       const struct btrfs_key *oldkey,
 					       u64 newlen, u64 frontpad)
 {
-	struct btrfs_stripe_extent *extent;
+	struct btrfs_root *stripe_root = trans->fs_info->stripe_root;
+	struct btrfs_stripe_extent *extent, *newitem;
 	struct extent_buffer *leaf;
 	int slot;
 	size_t item_size;
@@ -27,23 +28,39 @@ static void btrfs_partially_delete_raid_extent(struct btrfs_trans_handle *trans,
 		.type = BTRFS_RAID_STRIPE_KEY,
 		.offset = newlen,
 	};
+	int ret;
 
+	ASSERT(newlen > 0);
 	ASSERT(oldkey->type == BTRFS_RAID_STRIPE_KEY);
 
 	leaf = path->nodes[0];
 	slot = path->slots[0];
 	item_size = btrfs_item_size(leaf, slot);
+
+	newitem = kzalloc(item_size, GFP_NOFS);
+	if (!newitem)
+		return -ENOMEM;
+
 	extent = btrfs_item_ptr(leaf, slot, struct btrfs_stripe_extent);
 
 	for (int i = 0; i < btrfs_num_raid_stripes(item_size); i++) {
 		struct btrfs_raid_stride *stride = &extent->strides[i];
 		u64 phys;
 
-		phys = btrfs_raid_stride_physical(leaf, stride);
-		btrfs_set_raid_stride_physical(leaf, stride, phys + frontpad);
+		phys = btrfs_raid_stride_physical(leaf, stride) + frontpad;
+		btrfs_set_stack_raid_stride_physical(&newitem->strides[i], phys);
 	}
 
-	btrfs_set_item_key_safe(trans, path, &newkey);
+	ret = btrfs_del_item(trans, stripe_root, path);
+	if (ret)
+		goto out;
+
+	btrfs_release_path(path);
+	ret = btrfs_insert_item(trans, stripe_root, &newkey, newitem, item_size);
+
+out:
+	kfree(newitem);
+	return ret;
 }
 
 int btrfs_delete_raid_extent(struct btrfs_trans_handle *trans, u64 start, u64 length)
@@ -59,9 +76,22 @@ int btrfs_delete_raid_extent(struct btrfs_trans_handle *trans, u64 start, u64 le
 	int slot;
 	int ret;
 
-	if (!stripe_root)
+	if (!btrfs_fs_incompat(fs_info, RAID_STRIPE_TREE) || !stripe_root)
 		return 0;
 
+	if (!btrfs_is_testing(fs_info)) {
+		struct btrfs_chunk_map *map;
+		bool use_rst;
+
+		map = btrfs_find_chunk_map(fs_info, start, length);
+		if (!map)
+			return -EINVAL;
+		use_rst = btrfs_need_stripe_tree_update(fs_info, map->type);
+		btrfs_free_chunk_map(map);
+		if (!use_rst)
+			return 0;
+	}
+
 	path = btrfs_alloc_path();
 	if (!path)
 		return -ENOMEM;
@@ -85,6 +115,37 @@ int btrfs_delete_raid_extent(struct btrfs_trans_handle *trans, u64 start, u64 le
 		found_end = found_start + key.offset;
 		ret = 0;
 
+		/*
+		 * The stripe extent starts before the range we want to delete,
+		 * but the range spans more than one stripe extent:
+		 *
+		 * |--- RAID Stripe Extent ---||--- RAID Stripe Extent ---|
+		 *        |--- keep  ---|--- drop ---|
+		 *
+		 * This means we have to get the previous item, truncate its
+		 * length and then restart the search.
+		 */
+		if (found_start > start) {
+			if (slot == 0) {
+				ret = btrfs_previous_item(stripe_root, path, start,
+							  BTRFS_RAID_STRIPE_KEY);
+				if (ret) {
+					if (ret > 0)
+						ret = -ENOENT;
+					break;
+				}
+			} else {
+				path->slots[0]--;
+			}
+
+			leaf = path->nodes[0];
+			slot = path->slots[0];
+			btrfs_item_key_to_cpu(leaf, &key, slot);
+			found_start = key.objectid;
+			found_end = found_start + key.offset;
+			ASSERT(found_start <= start);
+		}
+
 		if (key.type != BTRFS_RAID_STRIPE_KEY)
 			break;
 
@@ -96,6 +157,54 @@ int btrfs_delete_raid_extent(struct btrfs_trans_handle *trans, u64 start, u64 le
 					       found_start, found_end);
 
 		/*
+		 * The stripe extent starts before the range we want to delete
+		 * and ends after the range we want to delete, i.e. we're
+		 * punching a hole in the stripe extent:
+		 *
+		 *  |--- RAID Stripe Extent ---|
+		 *  | keep |--- drop ---| keep |
+		 *
+		 * This means we need to a) truncate the existing item and b)
+		 * create a second item for the remaining range.
+		 */
+		if (found_start < start && found_end > end) {
+			size_t item_size;
+			u64 diff_start = start - found_start;
+			u64 diff_end = found_end - end;
+			struct btrfs_stripe_extent *extent;
+			struct btrfs_key newkey = {
+				.objectid = end,
+				.type = BTRFS_RAID_STRIPE_KEY,
+				.offset = diff_end,
+			};
+
+			/* The "right" item. */
+			ret = btrfs_duplicate_item(trans, stripe_root, path, &newkey);
+			if (ret)
+				break;
+
+			item_size = btrfs_item_size(leaf, path->slots[0]);
+			extent = btrfs_item_ptr(leaf, path->slots[0],
+						struct btrfs_stripe_extent);
+
+			for (int i = 0; i < btrfs_num_raid_stripes(item_size); i++) {
+				struct btrfs_raid_stride *stride = &extent->strides[i];
+				u64 phys;
+
+				phys = btrfs_raid_stride_physical(leaf, stride);
+				phys += diff_start + length;
+				btrfs_set_raid_stride_physical(leaf, stride, phys);
+			}
+
+			/* The "left" item. */
+			path->slots[0]--;
+			btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
+			btrfs_partially_delete_raid_extent(trans, path, &key,
+							   diff_start, 0);
+			break;
+		}
+
+		/*
 		 * The stripe extent starts before the range we want to delete:
 		 *
 		 * |--- RAID Stripe Extent ---|
@@ -105,11 +214,18 @@ int btrfs_delete_raid_extent(struct btrfs_trans_handle *trans, u64 start, u64 le
 		 * length to the new size and then re-insert the item.
 		 */
 		if (found_start < start) {
-			u64 diff = start - found_start;
+			u64 diff_start = start - found_start;
 
 			btrfs_partially_delete_raid_extent(trans, path, &key,
-							   diff, 0);
-			break;
+							   diff_start, 0);
+
+			start += (key.offset - diff_start);
+			length -= (key.offset - diff_start);
+			if (length == 0)
+				break;
+
+			btrfs_release_path(path);
+			continue;
 		}
 
 		/*
@@ -122,13 +238,16 @@ int btrfs_delete_raid_extent(struct btrfs_trans_handle *trans, u64 start, u64 le
 		 * length to the new size and then re-insert the item.
 		 */
 		if (found_end > end) {
-			u64 diff = found_end - end;
+			u64 diff_end = found_end - end;
 
 			btrfs_partially_delete_raid_extent(trans, path, &key,
-							   diff, diff);
+							   key.offset - length,
+							   length);
+			ASSERT(key.offset - diff_end == length);
 			break;
 		}
 
+		/* Finally we can delete the whole item, no more special cases. */
 		ret = btrfs_del_item(trans, stripe_root, path);
 		if (ret)
 			break;
@@ -169,7 +288,6 @@ static int update_raid_extent_item(struct btrfs_trans_handle *trans,
 
 	write_extent_buffer(leaf, stripe_extent, btrfs_item_ptr_offset(leaf, slot),
 			    item_size);
-	btrfs_mark_buffer_dirty(trans, leaf);
 	btrfs_free_path(path);
 
 	return ret;
@@ -199,12 +317,8 @@ int btrfs_insert_one_raid_extent(struct btrfs_trans_handle *trans,
 	for (int i = 0; i < num_stripes; i++) {
 		u64 devid = bioc->stripes[i].dev->devid;
 		u64 physical = bioc->stripes[i].physical;
-		u64 length = bioc->stripes[i].length;
 		struct btrfs_raid_stride *raid_stride = &stripe_extent->strides[i];
 
-		if (length == 0)
-			length = bioc->size;
-
 		btrfs_set_stack_raid_stride_devid(raid_stride, devid);
 		btrfs_set_stack_raid_stride_physical(raid_stride, physical);
 	}
diff --git a/fs/btrfs/relocation.c b/fs/btrfs/relocation.c
index db8b42f6..af0969b 100644
--- a/fs/btrfs/relocation.c
+++ b/fs/btrfs/relocation.c
@@ -342,12 +342,6 @@ static bool handle_useless_nodes(struct reloc_control *rc,
 		if (cur == node)
 			ret = true;
 
-		/* The node is the lowest node */
-		if (cur->lowest) {
-			list_del_init(&cur->lower);
-			cur->lowest = 0;
-		}
-
 		/* Cleanup the lower edges */
 		while (!list_empty(&cur->lower)) {
 			struct btrfs_backref_edge *edge;
@@ -373,7 +367,6 @@ static bool handle_useless_nodes(struct reloc_control *rc,
 		 * cache to avoid unnecessary backref lookup.
 		 */
 		if (cur->level > 0) {
-			list_add(&cur->list, &cache->detached);
 			cur->detached = 1;
 		} else {
 			rb_erase(&cur->rb_node, &cache->rb_root);
@@ -426,7 +419,6 @@ static noinline_for_stack struct btrfs_backref_node *build_backref_tree(
 		goto out;
 	}
 
-	node->lowest = 1;
 	cur = node;
 
 	/* Breadth-first search to build backref cache */
@@ -470,92 +462,6 @@ static noinline_for_stack struct btrfs_backref_node *build_backref_tree(
 }
 
 /*
- * helper to add backref node for the newly created snapshot.
- * the backref node is created by cloning backref node that
- * corresponds to root of source tree
- */
-static int clone_backref_node(struct btrfs_trans_handle *trans,
-			      struct reloc_control *rc,
-			      const struct btrfs_root *src,
-			      struct btrfs_root *dest)
-{
-	struct btrfs_root *reloc_root = src->reloc_root;
-	struct btrfs_backref_cache *cache = &rc->backref_cache;
-	struct btrfs_backref_node *node = NULL;
-	struct btrfs_backref_node *new_node;
-	struct btrfs_backref_edge *edge;
-	struct btrfs_backref_edge *new_edge;
-	struct rb_node *rb_node;
-
-	rb_node = rb_simple_search(&cache->rb_root, src->commit_root->start);
-	if (rb_node) {
-		node = rb_entry(rb_node, struct btrfs_backref_node, rb_node);
-		if (node->detached)
-			node = NULL;
-		else
-			BUG_ON(node->new_bytenr != reloc_root->node->start);
-	}
-
-	if (!node) {
-		rb_node = rb_simple_search(&cache->rb_root,
-					   reloc_root->commit_root->start);
-		if (rb_node) {
-			node = rb_entry(rb_node, struct btrfs_backref_node,
-					rb_node);
-			BUG_ON(node->detached);
-		}
-	}
-
-	if (!node)
-		return 0;
-
-	new_node = btrfs_backref_alloc_node(cache, dest->node->start,
-					    node->level);
-	if (!new_node)
-		return -ENOMEM;
-
-	new_node->lowest = node->lowest;
-	new_node->checked = 1;
-	new_node->root = btrfs_grab_root(dest);
-	ASSERT(new_node->root);
-
-	if (!node->lowest) {
-		list_for_each_entry(edge, &node->lower, list[UPPER]) {
-			new_edge = btrfs_backref_alloc_edge(cache);
-			if (!new_edge)
-				goto fail;
-
-			btrfs_backref_link_edge(new_edge, edge->node[LOWER],
-						new_node, LINK_UPPER);
-		}
-	} else {
-		list_add_tail(&new_node->lower, &cache->leaves);
-	}
-
-	rb_node = rb_simple_insert(&cache->rb_root, new_node->bytenr,
-				   &new_node->rb_node);
-	if (rb_node)
-		btrfs_backref_panic(trans->fs_info, new_node->bytenr, -EEXIST);
-
-	if (!new_node->lowest) {
-		list_for_each_entry(new_edge, &new_node->lower, list[UPPER]) {
-			list_add_tail(&new_edge->list[LOWER],
-				      &new_edge->node[LOWER]->upper);
-		}
-	}
-	return 0;
-fail:
-	while (!list_empty(&new_node->lower)) {
-		new_edge = list_entry(new_node->lower.next,
-				      struct btrfs_backref_edge, list[UPPER]);
-		list_del(&new_edge->list[UPPER]);
-		btrfs_backref_free_edge(cache, new_edge);
-	}
-	btrfs_backref_free_node(cache, new_node);
-	return -ENOMEM;
-}
-
-/*
  * helper to add 'address of tree root -> reloc tree' mapping
  */
 static int __add_reloc_root(struct btrfs_root *root)
@@ -950,7 +856,6 @@ int replace_file_extents(struct btrfs_trans_handle *trans,
 	u32 i;
 	int ret = 0;
 	int first = 1;
-	int dirty = 0;
 
 	if (rc->stage != UPDATE_DATA_PTRS)
 		return 0;
@@ -1030,7 +935,6 @@ int replace_file_extents(struct btrfs_trans_handle *trans,
 		}
 
 		btrfs_set_file_extent_disk_bytenr(leaf, fi, new_bytenr);
-		dirty = 1;
 
 		key.offset -= btrfs_file_extent_offset(leaf, fi);
 		ref.action = BTRFS_ADD_DELAYED_REF;
@@ -1061,8 +965,6 @@ int replace_file_extents(struct btrfs_trans_handle *trans,
 			break;
 		}
 	}
-	if (dirty)
-		btrfs_mark_buffer_dirty(trans, leaf);
 	if (inode)
 		btrfs_add_delayed_iput(inode);
 	return ret;
@@ -1255,13 +1157,11 @@ int replace_path(struct btrfs_trans_handle *trans, struct reloc_control *rc,
 		 */
 		btrfs_set_node_blockptr(parent, slot, new_bytenr);
 		btrfs_set_node_ptr_generation(parent, slot, new_ptr_gen);
-		btrfs_mark_buffer_dirty(trans, parent);
 
 		btrfs_set_node_blockptr(path->nodes[level],
 					path->slots[level], old_bytenr);
 		btrfs_set_node_ptr_generation(path->nodes[level],
 					      path->slots[level], old_ptr_gen);
-		btrfs_mark_buffer_dirty(trans, path->nodes[level]);
 
 		ref.action = BTRFS_ADD_DELAYED_REF;
 		ref.bytenr = old_bytenr;
@@ -2058,100 +1958,72 @@ struct btrfs_root *select_reloc_root(struct btrfs_trans_handle *trans,
 	int index = 0;
 	int ret;
 
-	next = node;
-	while (1) {
-		cond_resched();
-		next = walk_up_backref(next, edges, &index);
-		root = next->root;
+	next = walk_up_backref(node, edges, &index);
+	root = next->root;
 
-		/*
-		 * If there is no root, then our references for this block are
-		 * incomplete, as we should be able to walk all the way up to a
-		 * block that is owned by a root.
-		 *
-		 * This path is only for SHAREABLE roots, so if we come upon a
-		 * non-SHAREABLE root then we have backrefs that resolve
-		 * improperly.
-		 *
-		 * Both of these cases indicate file system corruption, or a bug
-		 * in the backref walking code.
-		 */
-		if (!root) {
-			ASSERT(0);
-			btrfs_err(trans->fs_info,
-		"bytenr %llu doesn't have a backref path ending in a root",
-				  node->bytenr);
-			return ERR_PTR(-EUCLEAN);
-		}
-		if (!test_bit(BTRFS_ROOT_SHAREABLE, &root->state)) {
-			ASSERT(0);
-			btrfs_err(trans->fs_info,
-	"bytenr %llu has multiple refs with one ending in a non-shareable root",
-				  node->bytenr);
-			return ERR_PTR(-EUCLEAN);
-		}
+	/*
+	 * If there is no root, then our references for this block are
+	 * incomplete, as we should be able to walk all the way up to a block
+	 * that is owned by a root.
+	 *
+	 * This path is only for SHAREABLE roots, so if we come upon a
+	 * non-SHAREABLE root then we have backrefs that resolve improperly.
+	 *
+	 * Both of these cases indicate file system corruption, or a bug in the
+	 * backref walking code.
+	 */
+	if (unlikely(!root)) {
+		btrfs_err(trans->fs_info,
+			  "bytenr %llu doesn't have a backref path ending in a root",
+			  node->bytenr);
+		return ERR_PTR(-EUCLEAN);
+	}
+	if (unlikely(!test_bit(BTRFS_ROOT_SHAREABLE, &root->state))) {
+		btrfs_err(trans->fs_info,
+			  "bytenr %llu has multiple refs with one ending in a non-shareable root",
+			  node->bytenr);
+		return ERR_PTR(-EUCLEAN);
+	}
 
-		if (btrfs_root_id(root) == BTRFS_TREE_RELOC_OBJECTID) {
-			ret = record_reloc_root_in_trans(trans, root);
-			if (ret)
-				return ERR_PTR(ret);
-			break;
-		}
-
-		ret = btrfs_record_root_in_trans(trans, root);
+	if (btrfs_root_id(root) == BTRFS_TREE_RELOC_OBJECTID) {
+		ret = record_reloc_root_in_trans(trans, root);
 		if (ret)
 			return ERR_PTR(ret);
-		root = root->reloc_root;
-
-		/*
-		 * We could have raced with another thread which failed, so
-		 * root->reloc_root may not be set, return ENOENT in this case.
-		 */
-		if (!root)
-			return ERR_PTR(-ENOENT);
-
-		if (next->new_bytenr != root->node->start) {
-			/*
-			 * We just created the reloc root, so we shouldn't have
-			 * ->new_bytenr set and this shouldn't be in the changed
-			 *  list.  If it is then we have multiple roots pointing
-			 *  at the same bytenr which indicates corruption, or
-			 *  we've made a mistake in the backref walking code.
-			 */
-			ASSERT(next->new_bytenr == 0);
-			ASSERT(list_empty(&next->list));
-			if (next->new_bytenr || !list_empty(&next->list)) {
-				btrfs_err(trans->fs_info,
-	"bytenr %llu possibly has multiple roots pointing at the same bytenr %llu",
-					  node->bytenr, next->bytenr);
-				return ERR_PTR(-EUCLEAN);
-			}
-
-			next->new_bytenr = root->node->start;
-			btrfs_put_root(next->root);
-			next->root = btrfs_grab_root(root);
-			ASSERT(next->root);
-			list_add_tail(&next->list,
-				      &rc->backref_cache.changed);
-			mark_block_processed(rc, next);
-			break;
-		}
-
-		WARN_ON(1);
-		root = NULL;
-		next = walk_down_backref(edges, &index);
-		if (!next || next->level <= node->level)
-			break;
+		goto found;
 	}
-	if (!root) {
-		/*
-		 * This can happen if there's fs corruption or if there's a bug
-		 * in the backref lookup code.
-		 */
-		ASSERT(0);
+
+	ret = btrfs_record_root_in_trans(trans, root);
+	if (ret)
+		return ERR_PTR(ret);
+	root = root->reloc_root;
+
+	/*
+	 * We could have raced with another thread which failed, so
+	 * root->reloc_root may not be set, return ENOENT in this case.
+	 */
+	if (!root)
 		return ERR_PTR(-ENOENT);
+
+	if (next->new_bytenr) {
+		/*
+		 * We just created the reloc root, so we shouldn't have
+		 * ->new_bytenr set yet. If it is then we have multiple roots
+		 *  pointing at the same bytenr which indicates corruption, or
+		 *  we've made a mistake in the backref walking code.
+		 */
+		ASSERT(next->new_bytenr == 0);
+		btrfs_err(trans->fs_info,
+			  "bytenr %llu possibly has multiple roots pointing at the same bytenr %llu",
+			  node->bytenr, next->bytenr);
+		return ERR_PTR(-EUCLEAN);
 	}
 
+	next->new_bytenr = root->node->start;
+	btrfs_put_root(next->root);
+	next->root = btrfs_grab_root(root);
+	ASSERT(next->root);
+	mark_block_processed(rc, next);
+found:
 	next = node;
 	/* setup backref node path for btrfs_reloc_cow_block */
 	while (1) {
@@ -2247,17 +2119,11 @@ static noinline_for_stack u64 calcu_metadata_size(struct reloc_control *rc,
 	return num_bytes;
 }
 
-static int reserve_metadata_space(struct btrfs_trans_handle *trans,
-				  struct reloc_control *rc,
-				  struct btrfs_backref_node *node)
+static int refill_metadata_space(struct btrfs_trans_handle *trans,
+				 struct reloc_control *rc, u64 num_bytes)
 {
-	struct btrfs_root *root = rc->extent_root;
-	struct btrfs_fs_info *fs_info = root->fs_info;
-	u64 num_bytes;
+	struct btrfs_fs_info *fs_info = trans->fs_info;
 	int ret;
-	u64 tmp;
-
-	num_bytes = calcu_metadata_size(rc, node) * 2;
 
 	trans->block_rsv = rc->block_rsv;
 	rc->reserved_bytes += num_bytes;
@@ -2270,7 +2136,8 @@ static int reserve_metadata_space(struct btrfs_trans_handle *trans,
 	ret = btrfs_block_rsv_refill(fs_info, rc->block_rsv, num_bytes,
 				     BTRFS_RESERVE_FLUSH_LIMIT);
 	if (ret) {
-		tmp = fs_info->nodesize * RELOCATION_RESERVED_NODES;
+		u64 tmp = fs_info->nodesize * RELOCATION_RESERVED_NODES;
+
 		while (tmp <= rc->reserved_bytes)
 			tmp <<= 1;
 		/*
@@ -2288,6 +2155,16 @@ static int reserve_metadata_space(struct btrfs_trans_handle *trans,
 	return 0;
 }
 
+static int reserve_metadata_space(struct btrfs_trans_handle *trans,
+				  struct reloc_control *rc,
+				  struct btrfs_backref_node *node)
+{
+	u64 num_bytes;
+
+	num_bytes = calcu_metadata_size(rc, node) * 2;
+	return refill_metadata_space(trans, rc, num_bytes);
+}
+
 /*
  * relocate a block tree, and then update pointers in upper level
  * blocks that reference the block to point to the new location.
@@ -2442,7 +2319,7 @@ static int do_relocation(struct btrfs_trans_handle *trans,
 
 	if (!ret && node->pending) {
 		btrfs_backref_drop_node_buffer(node);
-		list_move_tail(&node->list, &rc->backref_cache.changed);
+		list_del_init(&node->list);
 		node->pending = 0;
 	}
 
@@ -2605,8 +2482,7 @@ static int relocate_tree_block(struct btrfs_trans_handle *trans,
 			/*
 			 * This block was the root block of a root, and this is
 			 * the first time we're processing the block and thus it
-			 * should not have had the ->new_bytenr modified and
-			 * should have not been included on the changed list.
+			 * should not have had the ->new_bytenr modified.
 			 *
 			 * However in the case of corruption we could have
 			 * multiple refs pointing to the same block improperly,
@@ -2616,8 +2492,7 @@ static int relocate_tree_block(struct btrfs_trans_handle *trans,
 			 * normal user in the case of corruption.
 			 */
 			ASSERT(node->new_bytenr == 0);
-			ASSERT(list_empty(&node->list));
-			if (node->new_bytenr || !list_empty(&node->list)) {
+			if (node->new_bytenr) {
 				btrfs_err(root->fs_info,
 				  "bytenr %llu has improper references to it",
 					  node->bytenr);
@@ -2640,17 +2515,12 @@ static int relocate_tree_block(struct btrfs_trans_handle *trans,
 			btrfs_put_root(node->root);
 			node->root = btrfs_grab_root(root);
 			ASSERT(node->root);
-			list_add_tail(&node->list, &rc->backref_cache.changed);
 		} else {
-			path->lowest_level = node->level;
-			if (root == root->fs_info->chunk_root)
-				btrfs_reserve_chunk_metadata(trans, false);
-			ret = btrfs_search_slot(trans, root, key, path, 0, 1);
-			btrfs_release_path(path);
-			if (root == root->fs_info->chunk_root)
-				btrfs_trans_release_chunk_metadata(trans);
-			if (ret > 0)
-				ret = 0;
+			btrfs_err(root->fs_info,
+				  "bytenr %llu resolved to a non-shareable root",
+				  node->bytenr);
+			ret = -EUCLEAN;
+			goto out;
 		}
 		if (!ret)
 			update_processed_blocks(rc, node);
@@ -2658,11 +2528,50 @@ static int relocate_tree_block(struct btrfs_trans_handle *trans,
 		ret = do_relocation(trans, rc, node, key, path, 1);
 	}
 out:
-	if (ret || node->level == 0 || node->cowonly)
+	if (ret || node->level == 0)
 		btrfs_backref_cleanup_node(&rc->backref_cache, node);
 	return ret;
 }
 
+static int relocate_cowonly_block(struct btrfs_trans_handle *trans,
+				  struct reloc_control *rc, struct tree_block *block,
+				  struct btrfs_path *path)
+{
+	struct btrfs_fs_info *fs_info = trans->fs_info;
+	struct btrfs_root *root;
+	u64 num_bytes;
+	int nr_levels;
+	int ret;
+
+	root = btrfs_get_fs_root(fs_info, block->owner, true);
+	if (IS_ERR(root))
+		return PTR_ERR(root);
+
+	nr_levels = max(btrfs_header_level(root->node) - block->level, 0) + 1;
+
+	num_bytes = fs_info->nodesize * nr_levels;
+	ret = refill_metadata_space(trans, rc, num_bytes);
+	if (ret) {
+		btrfs_put_root(root);
+		return ret;
+	}
+	path->lowest_level = block->level;
+	if (root == root->fs_info->chunk_root)
+		btrfs_reserve_chunk_metadata(trans, false);
+
+	ret = btrfs_search_slot(trans, root, &block->key, path, 0, 1);
+	path->lowest_level = 0;
+	btrfs_release_path(path);
+
+	if (root == root->fs_info->chunk_root)
+		btrfs_trans_release_chunk_metadata(trans);
+	if (ret > 0)
+		ret = 0;
+	btrfs_put_root(root);
+
+	return ret;
+}
+
 /*
  * relocate a list of blocks
  */
@@ -2702,6 +2611,20 @@ int relocate_tree_blocks(struct btrfs_trans_handle *trans,
 
 	/* Do tree relocation */
 	rbtree_postorder_for_each_entry_safe(block, next, blocks, rb_node) {
+		/*
+		 * For COWonly blocks, or the data reloc tree, we only need to
+		 * COW down to the block, there's no need to generate a backref
+		 * tree.
+		 */
+		if (block->owner &&
+		    (!is_fstree(block->owner) ||
+		     block->owner == BTRFS_DATA_RELOC_TREE_OBJECTID)) {
+			ret = relocate_cowonly_block(trans, rc, block, path);
+			if (ret)
+				break;
+			continue;
+		}
+
 		node = build_backref_tree(trans, rc, &block->key,
 					  block->level, block->bytenr);
 		if (IS_ERR(node)) {
@@ -2947,7 +2870,7 @@ static int relocate_one_folio(struct reloc_control *rc,
 
 	/*
 	 * We could have lost folio private when we dropped the lock to read the
-	 * folio above, make sure we set_page_extent_mapped here so we have any
+	 * folio above, make sure we set_folio_extent_mapped() here so we have any
 	 * of the subpage blocksize stuff we need in place.
 	 */
 	ret = set_folio_extent_mapped(folio);
@@ -3799,7 +3722,6 @@ static int __insert_orphan_inode(struct btrfs_trans_handle *trans,
 	btrfs_set_inode_mode(leaf, item, S_IFREG | 0600);
 	btrfs_set_inode_flags(leaf, item, BTRFS_INODE_NOCOMPRESS |
 					  BTRFS_INODE_PREALLOC);
-	btrfs_mark_buffer_dirty(trans, leaf);
 out:
 	btrfs_free_path(path);
 	return ret;
@@ -4405,8 +4327,18 @@ int btrfs_reloc_cow_block(struct btrfs_trans_handle *trans,
 		WARN_ON(!first_cow && level == 0);
 
 		node = rc->backref_cache.path[level];
-		BUG_ON(node->bytenr != buf->start &&
-		       node->new_bytenr != buf->start);
+
+		/*
+		 * If node->bytenr != buf->start and node->new_bytenr !=
+		 * buf->start then we've got the wrong backref node for what we
+		 * expected to see here and the cache is incorrect.
+		 */
+		if (unlikely(node->bytenr != buf->start && node->new_bytenr != buf->start)) {
+			btrfs_err(fs_info,
+"bytenr %llu was found but our backref cache was expecting %llu or %llu",
+				  buf->start, node->bytenr, node->new_bytenr);
+			return -EUCLEAN;
+		}
 
 		btrfs_backref_drop_node_buffer(node);
 		atomic_inc(&cow->refs);
@@ -4506,10 +4438,7 @@ int btrfs_reloc_post_snapshot(struct btrfs_trans_handle *trans,
 		return ret;
 	}
 	new_root->reloc_root = btrfs_grab_root(reloc_root);
-
-	if (rc->create_reloc_tree)
-		ret = clone_backref_node(trans, rc, root, reloc_root);
-	return ret;
+	return 0;
 }
 
 /*
diff --git a/fs/btrfs/root-tree.c b/fs/btrfs/root-tree.c
index 3396267..e22e6b0 100644
--- a/fs/btrfs/root-tree.c
+++ b/fs/btrfs/root-tree.c
@@ -197,7 +197,6 @@ int btrfs_update_root(struct btrfs_trans_handle *trans, struct btrfs_root
 	btrfs_set_root_generation_v2(item, btrfs_root_generation(item));
 
 	write_extent_buffer(l, item, ptr, sizeof(*item));
-	btrfs_mark_buffer_dirty(trans, path->nodes[0]);
 out:
 	btrfs_free_path(path);
 	return ret;
@@ -447,7 +446,6 @@ int btrfs_add_root_ref(struct btrfs_trans_handle *trans, u64 root_id,
 	btrfs_set_root_ref_name_len(leaf, ref, name->len);
 	ptr = (unsigned long)(ref + 1);
 	write_extent_buffer(leaf, name->name, ptr, name->len);
-	btrfs_mark_buffer_dirty(trans, leaf);
 
 	if (key.type == BTRFS_ROOT_BACKREF_KEY) {
 		btrfs_release_path(path);
diff --git a/fs/btrfs/send.c b/fs/btrfs/send.c
index 498c843..f437138 100644
--- a/fs/btrfs/send.c
+++ b/fs/btrfs/send.c
@@ -7259,7 +7259,7 @@ static int changed_cb(struct btrfs_path *left_path,
 		      enum btrfs_compare_tree_result result,
 		      struct send_ctx *sctx)
 {
-	int ret = 0;
+	int ret;
 
 	/*
 	 * We can not hold the commit root semaphore here. This is because in
@@ -7319,7 +7319,6 @@ static int changed_cb(struct btrfs_path *left_path,
 			return 0;
 		}
 		result = BTRFS_COMPARE_TREE_CHANGED;
-		ret = 0;
 	}
 
 	sctx->left_path = left_path;
diff --git a/fs/btrfs/space-info.c b/fs/btrfs/space-info.c
index 255e85f..a341d08 100644
--- a/fs/btrfs/space-info.c
+++ b/fs/btrfs/space-info.c
@@ -14,6 +14,7 @@
 #include "fs.h"
 #include "accessors.h"
 #include "extent-tree.h"
+#include "zoned.h"
 
 /*
  * HOW DOES SPACE RESERVATION WORK
@@ -127,6 +128,14 @@
  *     churn a lot and we can avoid making some extent tree modifications if we
  *     are able to delay for as long as possible.
  *
+ *   RESET_ZONES
+ *     This state works only for the zoned mode. On the zoned mode, we cannot
+ *     reuse once allocated then freed region until we reset the zone, due to
+ *     the sequential write zone requirement. The RESET_ZONES state resets the
+ *     zones of an unused block group and let us reuse the space. The reusing
+ *     is faster than removing the block group and allocating another block
+ *     group on the zones.
+ *
  *   ALLOC_CHUNK
  *     We will skip this the first time through space reservation, because of
  *     overcommit and we don't want to have a lot of useless metadata space when
@@ -316,7 +325,7 @@ void btrfs_add_bg_to_space_info(struct btrfs_fs_info *info,
 	found->bytes_used += block_group->used;
 	found->disk_used += block_group->used * factor;
 	found->bytes_readonly += block_group->bytes_super;
-	btrfs_space_info_update_bytes_zone_unusable(info, found, block_group->zone_unusable);
+	btrfs_space_info_update_bytes_zone_unusable(found, block_group->zone_unusable);
 	if (block_group->length > 0)
 		found->full = 0;
 	btrfs_try_granting_tickets(info, found);
@@ -489,9 +498,7 @@ void btrfs_try_granting_tickets(struct btrfs_fs_info *fs_info,
 		if ((used + ticket->bytes <= space_info->total_bytes) ||
 		    btrfs_can_overcommit(fs_info, space_info, ticket->bytes,
 					 flush)) {
-			btrfs_space_info_update_bytes_may_use(fs_info,
-							      space_info,
-							      ticket->bytes);
+			btrfs_space_info_update_bytes_may_use(space_info, ticket->bytes);
 			remove_ticket(space_info, ticket);
 			ticket->bytes = 0;
 			space_info->tickets_id++;
@@ -834,6 +841,9 @@ static void flush_space(struct btrfs_fs_info *fs_info,
 		 */
 		ret = btrfs_commit_current_transaction(root);
 		break;
+	case RESET_ZONES:
+		ret = btrfs_reset_unused_block_groups(space_info, num_bytes);
+		break;
 	default:
 		ret = -ENOSPC;
 		break;
@@ -1086,9 +1096,14 @@ static void btrfs_async_reclaim_metadata_space(struct work_struct *work)
 	enum btrfs_flush_state flush_state;
 	int commit_cycles = 0;
 	u64 last_tickets_id;
+	enum btrfs_flush_state final_state;
 
 	fs_info = container_of(work, struct btrfs_fs_info, async_reclaim_work);
 	space_info = btrfs_find_space_info(fs_info, BTRFS_BLOCK_GROUP_METADATA);
+	if (btrfs_is_zoned(fs_info))
+		final_state = RESET_ZONES;
+	else
+		final_state = COMMIT_TRANS;
 
 	spin_lock(&space_info->lock);
 	to_reclaim = btrfs_calc_reclaim_metadata_size(fs_info, space_info);
@@ -1141,7 +1156,7 @@ static void btrfs_async_reclaim_metadata_space(struct work_struct *work)
 		if (flush_state == ALLOC_CHUNK_FORCE && !commit_cycles)
 			flush_state++;
 
-		if (flush_state > COMMIT_TRANS) {
+		if (flush_state > final_state) {
 			commit_cycles++;
 			if (commit_cycles > 2) {
 				if (maybe_fail_all_tickets(fs_info, space_info)) {
@@ -1155,7 +1170,7 @@ static void btrfs_async_reclaim_metadata_space(struct work_struct *work)
 			}
 		}
 		spin_unlock(&space_info->lock);
-	} while (flush_state <= COMMIT_TRANS);
+	} while (flush_state <= final_state);
 }
 
 /*
@@ -1286,6 +1301,10 @@ static void btrfs_preempt_reclaim_metadata_space(struct work_struct *work)
  *   This is where we reclaim all of the pinned space generated by running the
  *   iputs
  *
+ * RESET_ZONES
+ *   This state works only for the zoned mode. We scan the unused block group
+ *   list and reset the zones and reuse the block group.
+ *
  * ALLOC_CHUNK_FORCE
  *   For data we start with alloc chunk force, however we could have been full
  *   before, and then the transaction commit could have freed new block groups,
@@ -1295,6 +1314,7 @@ static const enum btrfs_flush_state data_flush_states[] = {
 	FLUSH_DELALLOC_FULL,
 	RUN_DELAYED_IPUTS,
 	COMMIT_TRANS,
+	RESET_ZONES,
 	ALLOC_CHUNK_FORCE,
 };
 
@@ -1386,6 +1406,7 @@ void btrfs_init_async_reclaim_work(struct btrfs_fs_info *fs_info)
 static const enum btrfs_flush_state priority_flush_states[] = {
 	FLUSH_DELAYED_ITEMS_NR,
 	FLUSH_DELAYED_ITEMS,
+	RESET_ZONES,
 	ALLOC_CHUNK,
 };
 
@@ -1399,6 +1420,7 @@ static const enum btrfs_flush_state evict_flush_states[] = {
 	FLUSH_DELALLOC_FULL,
 	ALLOC_CHUNK,
 	COMMIT_TRANS,
+	RESET_ZONES,
 };
 
 static void priority_reclaim_metadata_space(struct btrfs_fs_info *fs_info,
@@ -1690,8 +1712,7 @@ static int __reserve_bytes(struct btrfs_fs_info *fs_info,
 	if (!pending_tickets &&
 	    ((used + orig_bytes <= space_info->total_bytes) ||
 	     btrfs_can_overcommit(fs_info, space_info, orig_bytes, flush))) {
-		btrfs_space_info_update_bytes_may_use(fs_info, space_info,
-						      orig_bytes);
+		btrfs_space_info_update_bytes_may_use(space_info, orig_bytes);
 		ret = 0;
 	}
 
@@ -1703,8 +1724,7 @@ static int __reserve_bytes(struct btrfs_fs_info *fs_info,
 	if (ret && unlikely(flush == BTRFS_RESERVE_FLUSH_EMERGENCY)) {
 		used = btrfs_space_info_used(space_info, false);
 		if (used + orig_bytes <= space_info->total_bytes) {
-			btrfs_space_info_update_bytes_may_use(fs_info, space_info,
-							      orig_bytes);
+			btrfs_space_info_update_bytes_may_use(space_info, orig_bytes);
 			ret = 0;
 		}
 	}
@@ -2082,3 +2102,32 @@ void btrfs_reclaim_sweep(const struct btrfs_fs_info *fs_info)
 			do_reclaim_sweep(space_info, raid);
 	}
 }
+
+void btrfs_return_free_space(struct btrfs_space_info *space_info, u64 len)
+{
+	struct btrfs_fs_info *fs_info = space_info->fs_info;
+	struct btrfs_block_rsv *global_rsv = &fs_info->global_block_rsv;
+
+	lockdep_assert_held(&space_info->lock);
+
+	/* Prioritize the global reservation to receive the freed space. */
+	if (global_rsv->space_info != space_info)
+		goto grant;
+
+	spin_lock(&global_rsv->lock);
+	if (!global_rsv->full) {
+		u64 to_add = min(len, global_rsv->size - global_rsv->reserved);
+
+		global_rsv->reserved += to_add;
+		btrfs_space_info_update_bytes_may_use(space_info, to_add);
+		if (global_rsv->reserved >= global_rsv->size)
+			global_rsv->full = 1;
+		len -= to_add;
+	}
+	spin_unlock(&global_rsv->lock);
+
+grant:
+	/* Add to any tickets we may have. */
+	if (len)
+		btrfs_try_granting_tickets(fs_info, space_info);
+}
diff --git a/fs/btrfs/space-info.h b/fs/btrfs/space-info.h
index efbecc0..a96efdb 100644
--- a/fs/btrfs/space-info.h
+++ b/fs/btrfs/space-info.h
@@ -79,6 +79,10 @@ enum btrfs_reserve_flush_enum {
 	BTRFS_RESERVE_FLUSH_EMERGENCY,
 };
 
+/*
+ * Please be aware that the order of enum values will be the order of the reclaim
+ * process in btrfs_async_reclaim_metadata_space().
+ */
 enum btrfs_flush_state {
 	FLUSH_DELAYED_ITEMS_NR	= 1,
 	FLUSH_DELAYED_ITEMS	= 2,
@@ -91,6 +95,7 @@ enum btrfs_flush_state {
 	ALLOC_CHUNK_FORCE	= 9,
 	RUN_DELAYED_IPUTS	= 10,
 	COMMIT_TRANS		= 11,
+	RESET_ZONES		= 12,
 };
 
 struct btrfs_space_info {
@@ -229,10 +234,10 @@ static inline bool btrfs_mixed_space_info(const struct btrfs_space_info *space_i
  */
 #define DECLARE_SPACE_INFO_UPDATE(name, trace_name)			\
 static inline void							\
-btrfs_space_info_update_##name(struct btrfs_fs_info *fs_info,		\
-			       struct btrfs_space_info *sinfo,		\
+btrfs_space_info_update_##name(struct btrfs_space_info *sinfo,		\
 			       s64 bytes)				\
 {									\
+	struct btrfs_fs_info *fs_info = sinfo->fs_info;			\
 	const u64 abs_bytes = (bytes < 0) ? -bytes : bytes;		\
 	lockdep_assert_held(&sinfo->lock);				\
 	trace_update_##name(fs_info, sinfo, sinfo->name, bytes);	\
@@ -275,13 +280,12 @@ int btrfs_can_overcommit(struct btrfs_fs_info *fs_info,
 			 enum btrfs_reserve_flush_enum flush);
 
 static inline void btrfs_space_info_free_bytes_may_use(
-				struct btrfs_fs_info *fs_info,
 				struct btrfs_space_info *space_info,
 				u64 num_bytes)
 {
 	spin_lock(&space_info->lock);
-	btrfs_space_info_update_bytes_may_use(fs_info, space_info, -num_bytes);
-	btrfs_try_granting_tickets(fs_info, space_info);
+	btrfs_space_info_update_bytes_may_use(space_info, -num_bytes);
+	btrfs_try_granting_tickets(space_info->fs_info, space_info);
 	spin_unlock(&space_info->lock);
 }
 int btrfs_reserve_data_bytes(struct btrfs_fs_info *fs_info, u64 bytes,
@@ -295,5 +299,6 @@ void btrfs_set_periodic_reclaim_ready(struct btrfs_space_info *space_info, bool
 bool btrfs_should_periodic_reclaim(struct btrfs_space_info *space_info);
 int btrfs_calc_reclaim_threshold(const struct btrfs_space_info *space_info);
 void btrfs_reclaim_sweep(const struct btrfs_fs_info *fs_info);
+void btrfs_return_free_space(struct btrfs_space_info *space_info, u64 len);
 
 #endif /* BTRFS_SPACE_INFO_H */
diff --git a/fs/btrfs/subpage.c b/fs/btrfs/subpage.c
index 8c68059..722acf7 100644
--- a/fs/btrfs/subpage.c
+++ b/fs/btrfs/subpage.c
@@ -635,6 +635,28 @@ IMPLEMENT_BTRFS_PAGE_OPS(ordered, folio_set_ordered, folio_clear_ordered,
 IMPLEMENT_BTRFS_PAGE_OPS(checked, folio_set_checked, folio_clear_checked,
 			 folio_test_checked);
 
+#define GET_SUBPAGE_BITMAP(subpage, fs_info, name, dst)			\
+{									\
+	const int sectors_per_page = fs_info->sectors_per_page;		\
+									\
+	ASSERT(sectors_per_page < BITS_PER_LONG);			\
+	*dst = bitmap_read(subpage->bitmaps,				\
+			   sectors_per_page * btrfs_bitmap_nr_##name,	\
+			   sectors_per_page);				\
+}
+
+#define SUBPAGE_DUMP_BITMAP(fs_info, folio, name, start, len)		\
+{									\
+	const struct btrfs_subpage *subpage = folio_get_private(folio);	\
+	unsigned long bitmap;						\
+									\
+	GET_SUBPAGE_BITMAP(subpage, fs_info, name, &bitmap);		\
+	btrfs_warn(fs_info,						\
+	"dumpping bitmap start=%llu len=%u folio=%llu " #name "_bitmap=%*pbl", \
+		   start, len, folio_pos(folio),			\
+		   fs_info->sectors_per_page, &bitmap);			\
+}
+
 /*
  * Make sure not only the page dirty bit is cleared, but also subpage dirty bit
  * is cleared.
@@ -660,6 +682,10 @@ void btrfs_folio_assert_not_dirty(const struct btrfs_fs_info *fs_info,
 	subpage = folio_get_private(folio);
 	ASSERT(subpage);
 	spin_lock_irqsave(&subpage->lock, flags);
+	if (unlikely(!bitmap_test_range_all_zero(subpage->bitmaps, start_bit, nbits))) {
+		SUBPAGE_DUMP_BITMAP(fs_info, folio, dirty, start, len);
+		ASSERT(bitmap_test_range_all_zero(subpage->bitmaps, start_bit, nbits));
+	}
 	ASSERT(bitmap_test_range_all_zero(subpage->bitmaps, start_bit, nbits));
 	spin_unlock_irqrestore(&subpage->lock, flags);
 }
@@ -689,23 +715,16 @@ void btrfs_folio_set_lock(const struct btrfs_fs_info *fs_info,
 	nbits = len >> fs_info->sectorsize_bits;
 	spin_lock_irqsave(&subpage->lock, flags);
 	/* Target range should not yet be locked. */
-	ASSERT(bitmap_test_range_all_zero(subpage->bitmaps, start_bit, nbits));
+	if (unlikely(!bitmap_test_range_all_zero(subpage->bitmaps, start_bit, nbits))) {
+		SUBPAGE_DUMP_BITMAP(fs_info, folio, locked, start, len);
+		ASSERT(bitmap_test_range_all_zero(subpage->bitmaps, start_bit, nbits));
+	}
 	bitmap_set(subpage->bitmaps, start_bit, nbits);
 	ret = atomic_add_return(nbits, &subpage->nr_locked);
 	ASSERT(ret <= fs_info->sectors_per_page);
 	spin_unlock_irqrestore(&subpage->lock, flags);
 }
 
-#define GET_SUBPAGE_BITMAP(subpage, fs_info, name, dst)			\
-{									\
-	const int sectors_per_page = fs_info->sectors_per_page;		\
-									\
-	ASSERT(sectors_per_page < BITS_PER_LONG);			\
-	*dst = bitmap_read(subpage->bitmaps,				\
-			   sectors_per_page * btrfs_bitmap_nr_##name,	\
-			   sectors_per_page);				\
-}
-
 void __cold btrfs_subpage_dump_bitmap(const struct btrfs_fs_info *fs_info,
 				      struct folio *folio, u64 start, u32 len)
 {
@@ -716,6 +735,7 @@ void __cold btrfs_subpage_dump_bitmap(const struct btrfs_fs_info *fs_info,
 	unsigned long writeback_bitmap;
 	unsigned long ordered_bitmap;
 	unsigned long checked_bitmap;
+	unsigned long locked_bitmap;
 	unsigned long flags;
 
 	ASSERT(folio_test_private(folio) && folio_get_private(folio));
@@ -728,15 +748,16 @@ void __cold btrfs_subpage_dump_bitmap(const struct btrfs_fs_info *fs_info,
 	GET_SUBPAGE_BITMAP(subpage, fs_info, writeback, &writeback_bitmap);
 	GET_SUBPAGE_BITMAP(subpage, fs_info, ordered, &ordered_bitmap);
 	GET_SUBPAGE_BITMAP(subpage, fs_info, checked, &checked_bitmap);
-	GET_SUBPAGE_BITMAP(subpage, fs_info, locked, &checked_bitmap);
+	GET_SUBPAGE_BITMAP(subpage, fs_info, locked, &locked_bitmap);
 	spin_unlock_irqrestore(&subpage->lock, flags);
 
 	dump_page(folio_page(folio, 0), "btrfs subpage dump");
 	btrfs_warn(fs_info,
-"start=%llu len=%u page=%llu, bitmaps uptodate=%*pbl dirty=%*pbl writeback=%*pbl ordered=%*pbl checked=%*pbl",
+"start=%llu len=%u page=%llu, bitmaps uptodate=%*pbl dirty=%*pbl locked=%*pbl writeback=%*pbl ordered=%*pbl checked=%*pbl",
 		    start, len, folio_pos(folio),
 		    sectors_per_page, &uptodate_bitmap,
 		    sectors_per_page, &dirty_bitmap,
+		    sectors_per_page, &locked_bitmap,
 		    sectors_per_page, &writeback_bitmap,
 		    sectors_per_page, &ordered_bitmap,
 		    sectors_per_page, &checked_bitmap);
diff --git a/fs/btrfs/subpage.h b/fs/btrfs/subpage.h
index 428fa93..44fff1f 100644
--- a/fs/btrfs/subpage.h
+++ b/fs/btrfs/subpage.h
@@ -137,6 +137,19 @@ DECLARE_BTRFS_SUBPAGE_OPS(writeback);
 DECLARE_BTRFS_SUBPAGE_OPS(ordered);
 DECLARE_BTRFS_SUBPAGE_OPS(checked);
 
+/*
+ * Helper for error cleanup, where a folio will have its dirty flag cleared,
+ * with writeback started and finished.
+ */
+static inline void btrfs_folio_clamp_finish_io(struct btrfs_fs_info *fs_info,
+					       struct folio *locked_folio,
+					       u64 start, u32 len)
+{
+	btrfs_folio_clamp_clear_dirty(fs_info, locked_folio, start, len);
+	btrfs_folio_clamp_set_writeback(fs_info, locked_folio, start, len);
+	btrfs_folio_clamp_clear_writeback(fs_info, locked_folio, start, len);
+}
+
 bool btrfs_subpage_clear_and_test_dirty(const struct btrfs_fs_info *fs_info,
 					struct folio *folio, u64 start, u32 len);
 
diff --git a/fs/btrfs/super.c b/fs/btrfs/super.c
index 7dfe500..f809c32 100644
--- a/fs/btrfs/super.c
+++ b/fs/btrfs/super.c
@@ -971,7 +971,7 @@ static int btrfs_fill_super(struct super_block *sb,
 
 	err = open_ctree(sb, fs_devices);
 	if (err) {
-		btrfs_err(fs_info, "open_ctree failed");
+		btrfs_err(fs_info, "open_ctree failed: %d", err);
 		return err;
 	}
 
@@ -2446,6 +2446,9 @@ static __cold void btrfs_interface_exit(void)
 static int __init btrfs_print_mod_info(void)
 {
 	static const char options[] = ""
+#ifdef CONFIG_BTRFS_EXPERIMENTAL
+			", experimental=on"
+#endif
 #ifdef CONFIG_BTRFS_DEBUG
 			", debug=on"
 #endif
@@ -2466,7 +2469,17 @@ static int __init btrfs_print_mod_info(void)
 			", fsverity=no"
 #endif
 			;
+
+#ifdef CONFIG_BTRFS_EXPERIMENTAL
+	if (btrfs_get_mod_read_policy() == NULL)
+		pr_info("Btrfs loaded%s\n", options);
+	else
+		pr_info("Btrfs loaded%s, read_policy=%s\n",
+			 options, btrfs_get_mod_read_policy());
+#else
 	pr_info("Btrfs loaded%s\n", options);
+#endif
+
 	return 0;
 }
 
@@ -2524,6 +2537,11 @@ static const struct init_sequence mod_init_seq[] = {
 	}, {
 		.init_func = extent_map_init,
 		.exit_func = extent_map_exit,
+#ifdef CONFIG_BTRFS_EXPERIMENTAL
+	}, {
+		.init_func = btrfs_read_policy_init,
+		.exit_func = NULL,
+#endif
 	}, {
 		.init_func = ordered_data_init,
 		.exit_func = ordered_data_exit,
diff --git a/fs/btrfs/sysfs.c b/fs/btrfs/sysfs.c
index 7f09b6c..53b846d 100644
--- a/fs/btrfs/sysfs.c
+++ b/fs/btrfs/sysfs.c
@@ -1305,7 +1305,73 @@ static ssize_t btrfs_temp_fsid_show(struct kobject *kobj,
 }
 BTRFS_ATTR(, temp_fsid, btrfs_temp_fsid_show);
 
-static const char * const btrfs_read_policy_name[] = { "pid" };
+static const char *btrfs_read_policy_name[] = {
+	"pid",
+#ifdef CONFIG_BTRFS_EXPERIMENTAL
+	"round-robin",
+	"devid",
+#endif
+};
+
+#ifdef CONFIG_BTRFS_EXPERIMENTAL
+
+/* Global module configuration parameters. */
+static char *read_policy;
+char *btrfs_get_mod_read_policy(void)
+{
+	return read_policy;
+}
+
+/* Set perms to 0, disable /sys/module/btrfs/parameter/read_policy interface. */
+module_param(read_policy, charp, 0);
+MODULE_PARM_DESC(read_policy,
+"Global read policy: pid (default), round-robin[:<min_contig_read>], devid[:<devid>]");
+#endif
+
+int btrfs_read_policy_to_enum(const char *str, s64 *value_ret)
+{
+	char param[32] = { 0 };
+	char __maybe_unused *value_str;
+
+	if (!str || strlen(str) == 0)
+		return 0;
+
+	strncpy(param, str, sizeof(param) - 1);
+
+#ifdef CONFIG_BTRFS_EXPERIMENTAL
+	/* Separate value from input in policy:value format. */
+	value_str = strchr(param, ':');
+	if (value_str) {
+		int ret;
+
+		*value_str = 0;
+		value_str++;
+		if (!value_ret)
+			return -EINVAL;
+		ret = kstrtos64(value_str, 10, value_ret);
+		if (ret)
+			return -EINVAL;
+		if (*value_ret < 0)
+			return -ERANGE;
+	}
+#endif
+
+	return sysfs_match_string(btrfs_read_policy_name, param);
+}
+
+#ifdef CONFIG_BTRFS_EXPERIMENTAL
+int __init btrfs_read_policy_init(void)
+{
+	s64 value;
+
+	if (btrfs_read_policy_to_enum(read_policy, &value) == -EINVAL) {
+		btrfs_err(NULL, "invalid read policy or value %s", read_policy);
+		return -EINVAL;
+	}
+
+	return 0;
+}
+#endif
 
 static ssize_t btrfs_read_policy_show(struct kobject *kobj,
 				      struct kobj_attribute *a, char *buf)
@@ -1316,14 +1382,25 @@ static ssize_t btrfs_read_policy_show(struct kobject *kobj,
 	int i;
 
 	for (i = 0; i < BTRFS_NR_READ_POLICY; i++) {
-		if (policy == i)
-			ret += sysfs_emit_at(buf, ret, "%s[%s]",
-					 (ret == 0 ? "" : " "),
-					 btrfs_read_policy_name[i]);
-		else
-			ret += sysfs_emit_at(buf, ret, "%s%s",
-					 (ret == 0 ? "" : " "),
-					 btrfs_read_policy_name[i]);
+		if (ret != 0)
+			ret += sysfs_emit_at(buf, ret, " ");
+
+		if (i == policy)
+			ret += sysfs_emit_at(buf, ret, "[");
+
+		ret += sysfs_emit_at(buf, ret, "%s", btrfs_read_policy_name[i]);
+
+#ifdef CONFIG_BTRFS_EXPERIMENTAL
+		if (i == BTRFS_READ_POLICY_RR)
+			ret += sysfs_emit_at(buf, ret, ":%u",
+					     READ_ONCE(fs_devices->rr_min_contig_read));
+
+		if (i == BTRFS_READ_POLICY_DEVID)
+			ret += sysfs_emit_at(buf, ret, ":%llu",
+					     READ_ONCE(fs_devices->read_devid));
+#endif
+		if (i == policy)
+			ret += sysfs_emit_at(buf, ret, "]");
 	}
 
 	ret += sysfs_emit_at(buf, ret, "\n");
@@ -1336,21 +1413,80 @@ static ssize_t btrfs_read_policy_store(struct kobject *kobj,
 				       const char *buf, size_t len)
 {
 	struct btrfs_fs_devices *fs_devices = to_fs_devs(kobj);
-	int i;
+	int index;
+	s64 value = -1;
 
-	for (i = 0; i < BTRFS_NR_READ_POLICY; i++) {
-		if (sysfs_streq(buf, btrfs_read_policy_name[i])) {
-			if (i != READ_ONCE(fs_devices->read_policy)) {
-				WRITE_ONCE(fs_devices->read_policy, i);
-				btrfs_info(fs_devices->fs_info,
-					   "read policy set to '%s'",
-					   btrfs_read_policy_name[i]);
+	index = btrfs_read_policy_to_enum(buf, &value);
+	if (index < 0)
+		return -EINVAL;
+
+#ifdef CONFIG_BTRFS_EXPERIMENTAL
+	/* If moving from RR then disable collecting fs stats. */
+	if (fs_devices->read_policy == BTRFS_READ_POLICY_RR && index != BTRFS_READ_POLICY_RR)
+		fs_devices->collect_fs_stats = false;
+
+	if (index == BTRFS_READ_POLICY_RR) {
+		if (value != -1) {
+			const u32 sectorsize = fs_devices->fs_info->sectorsize;
+
+			if (!IS_ALIGNED(value, sectorsize)) {
+				u64 temp_value = round_up(value, sectorsize);
+
+				btrfs_debug(fs_devices->fs_info,
+"read_policy: min contig read %lld should be multiple of sectorsize %u, rounded to %llu",
+					  value, sectorsize, temp_value);
+				value = temp_value;
 			}
-			return len;
+		} else {
+			value = BTRFS_DEFAULT_RR_MIN_CONTIG_READ;
 		}
+
+		if (index != READ_ONCE(fs_devices->read_policy) ||
+		    value != READ_ONCE(fs_devices->rr_min_contig_read)) {
+			WRITE_ONCE(fs_devices->read_policy, index);
+			WRITE_ONCE(fs_devices->rr_min_contig_read, value);
+
+			btrfs_info(fs_devices->fs_info, "read policy set to '%s:%lld'",
+				   btrfs_read_policy_name[index], value);
+		}
+
+		fs_devices->collect_fs_stats = true;
+
+		return len;
 	}
 
-	return -EINVAL;
+	if (index == BTRFS_READ_POLICY_DEVID) {
+		if (value != -1) {
+			BTRFS_DEV_LOOKUP_ARGS(args);
+
+			/* Validate input devid. */
+			args.devid = value;
+			if (btrfs_find_device(fs_devices, &args) == NULL)
+				return -EINVAL;
+		} else {
+			/* Set default devid to the devid of the latest device. */
+			value = fs_devices->latest_dev->devid;
+		}
+
+		if (index != READ_ONCE(fs_devices->read_policy) ||
+		    value != READ_ONCE(fs_devices->read_devid)) {
+			WRITE_ONCE(fs_devices->read_policy, index);
+			WRITE_ONCE(fs_devices->read_devid, value);
+
+			btrfs_info(fs_devices->fs_info, "read policy set to '%s:%llu'",
+				   btrfs_read_policy_name[index], value);
+		}
+
+		return len;
+	}
+#endif
+	if (index != READ_ONCE(fs_devices->read_policy)) {
+		WRITE_ONCE(fs_devices->read_policy, index);
+		btrfs_info(fs_devices->fs_info, "read policy set to '%s'",
+			   btrfs_read_policy_name[index]);
+	}
+
+	return len;
 }
 BTRFS_ATTR_RW(, read_policy, btrfs_read_policy_show, btrfs_read_policy_store);
 
diff --git a/fs/btrfs/sysfs.h b/fs/btrfs/sysfs.h
index e6a284c..3fc5c6f 100644
--- a/fs/btrfs/sysfs.h
+++ b/fs/btrfs/sysfs.h
@@ -47,5 +47,11 @@ void btrfs_sysfs_del_qgroups(struct btrfs_fs_info *fs_info);
 int btrfs_sysfs_add_qgroups(struct btrfs_fs_info *fs_info);
 void btrfs_sysfs_del_one_qgroup(struct btrfs_fs_info *fs_info,
 				struct btrfs_qgroup *qgroup);
+int btrfs_read_policy_to_enum(const char *str, s64 *value);
+
+#ifdef CONFIG_BTRFS_EXPERIMENTAL
+int __init btrfs_read_policy_init(void);
+char *btrfs_get_mod_read_policy(void);
+#endif
 
 #endif
diff --git a/fs/btrfs/tests/btrfs-tests.c b/fs/btrfs/tests/btrfs-tests.c
index e607b5d..5eff8d7 100644
--- a/fs/btrfs/tests/btrfs-tests.c
+++ b/fs/btrfs/tests/btrfs-tests.c
@@ -30,6 +30,7 @@ const char *test_error[] = {
 	[TEST_ALLOC_EXTENT_MAP]      = "cannot allocate extent map",
 	[TEST_ALLOC_CHUNK_MAP]       = "cannot allocate chunk map",
 	[TEST_ALLOC_IO_CONTEXT]	     = "cannot allocate io context",
+	[TEST_ALLOC_TRANSACTION]     = "cannot allocate transaction",
 };
 
 static const struct super_operations btrfs_test_super_ops = {
@@ -142,6 +143,11 @@ struct btrfs_fs_info *btrfs_alloc_dummy_fs_info(u32 nodesize, u32 sectorsize)
 	fs_info->nodesize = nodesize;
 	fs_info->sectorsize = sectorsize;
 	fs_info->sectorsize_bits = ilog2(sectorsize);
+
+	/* CRC32C csum size. */
+	fs_info->csum_size = 4;
+	fs_info->csums_per_leaf = BTRFS_MAX_ITEM_SIZE(fs_info) /
+		fs_info->csum_size;
 	set_bit(BTRFS_FS_STATE_DUMMY_FS_INFO, &fs_info->fs_state);
 
 	test_mnt->mnt_sb->s_fs_info = fs_info;
@@ -247,6 +253,15 @@ void btrfs_free_dummy_block_group(struct btrfs_block_group *cache)
 	kfree(cache);
 }
 
+void btrfs_init_dummy_transaction(struct btrfs_transaction *trans, struct btrfs_fs_info *fs_info)
+{
+	memset(trans, 0, sizeof(*trans));
+	trans->fs_info = fs_info;
+	xa_init(&trans->delayed_refs.head_refs);
+	xa_init(&trans->delayed_refs.dirty_extents);
+	spin_lock_init(&trans->delayed_refs.lock);
+}
+
 void btrfs_init_dummy_trans(struct btrfs_trans_handle *trans,
 			    struct btrfs_fs_info *fs_info)
 {
@@ -295,6 +310,9 @@ int btrfs_run_sanity_tests(void)
 			ret = btrfs_test_raid_stripe_tree(sectorsize, nodesize);
 			if (ret)
 				goto out;
+			ret = btrfs_test_delayed_refs(sectorsize, nodesize);
+			if (ret)
+				goto out;
 		}
 	}
 	ret = btrfs_test_extent_map();
diff --git a/fs/btrfs/tests/btrfs-tests.h b/fs/btrfs/tests/btrfs-tests.h
index b524ecf..4307bda 100644
--- a/fs/btrfs/tests/btrfs-tests.h
+++ b/fs/btrfs/tests/btrfs-tests.h
@@ -6,6 +6,8 @@
 #ifndef BTRFS_TESTS_H
 #define BTRFS_TESTS_H
 
+#include <linux/types.h>
+
 #ifdef CONFIG_BTRFS_FS_RUN_SANITY_TESTS
 int btrfs_run_sanity_tests(void);
 
@@ -25,12 +27,14 @@ enum {
 	TEST_ALLOC_EXTENT_MAP,
 	TEST_ALLOC_CHUNK_MAP,
 	TEST_ALLOC_IO_CONTEXT,
+	TEST_ALLOC_TRANSACTION,
 };
 
 extern const char *test_error[];
 
 struct btrfs_root;
 struct btrfs_trans_handle;
+struct btrfs_transaction;
 
 int btrfs_test_extent_buffer_operations(u32 sectorsize, u32 nodesize);
 int btrfs_test_free_space_cache(u32 sectorsize, u32 nodesize);
@@ -40,6 +44,7 @@ int btrfs_test_qgroups(u32 sectorsize, u32 nodesize);
 int btrfs_test_free_space_tree(u32 sectorsize, u32 nodesize);
 int btrfs_test_raid_stripe_tree(u32 sectorsize, u32 nodesize);
 int btrfs_test_extent_map(void);
+int btrfs_test_delayed_refs(u32 sectorsize, u32 nodesize);
 struct inode *btrfs_new_test_inode(void);
 struct btrfs_fs_info *btrfs_alloc_dummy_fs_info(u32 nodesize, u32 sectorsize);
 void btrfs_free_dummy_fs_info(struct btrfs_fs_info *fs_info);
@@ -49,6 +54,7 @@ btrfs_alloc_dummy_block_group(struct btrfs_fs_info *fs_info, unsigned long lengt
 void btrfs_free_dummy_block_group(struct btrfs_block_group *cache);
 void btrfs_init_dummy_trans(struct btrfs_trans_handle *trans,
 			    struct btrfs_fs_info *fs_info);
+void btrfs_init_dummy_transaction(struct btrfs_transaction *trans, struct btrfs_fs_info *fs_info);
 struct btrfs_device *btrfs_alloc_dummy_device(struct btrfs_fs_info *fs_info);
 #else
 static inline int btrfs_run_sanity_tests(void)
diff --git a/fs/btrfs/tests/delayed-refs-tests.c b/fs/btrfs/tests/delayed-refs-tests.c
new file mode 100644
index 0000000..6558508
--- /dev/null
+++ b/fs/btrfs/tests/delayed-refs-tests.c
@@ -0,0 +1,1015 @@
+// SPDX-License-Identifier: GPL-2.0
+#include <linux/sizes.h>
+#include "btrfs-tests.h"
+#include "../transaction.h"
+#include "../delayed-ref.h"
+#include "../extent-tree.h"
+
+#define FAKE_ROOT_OBJECTID 256
+#define FAKE_BYTENR 0
+#define FAKE_LEVEL 1
+#define FAKE_INO 256
+#define FAKE_FILE_OFFSET 0
+#define FAKE_PARENT SZ_1M
+
+struct ref_head_check {
+	u64 bytenr;
+	u64 num_bytes;
+	int ref_mod;
+	int total_ref_mod;
+	int must_insert;
+};
+
+struct ref_node_check {
+	u64 bytenr;
+	u64 num_bytes;
+	int ref_mod;
+	enum btrfs_delayed_ref_action action;
+	u8 type;
+	u64 parent;
+	u64 root;
+	u64 owner;
+	u64 offset;
+};
+
+static enum btrfs_ref_type ref_type_from_disk_ref_type(u8 type)
+{
+	if ((type == BTRFS_TREE_BLOCK_REF_KEY) ||
+	    (type == BTRFS_SHARED_BLOCK_REF_KEY))
+		return BTRFS_REF_METADATA;
+	return BTRFS_REF_DATA;
+}
+
+static void delete_delayed_ref_head(struct btrfs_trans_handle *trans,
+				    struct btrfs_delayed_ref_head *head)
+{
+	struct btrfs_fs_info *fs_info = trans->fs_info;
+	struct btrfs_delayed_ref_root *delayed_refs =
+		&trans->transaction->delayed_refs;
+
+	spin_lock(&delayed_refs->lock);
+	spin_lock(&head->lock);
+	btrfs_delete_ref_head(fs_info, delayed_refs, head);
+	spin_unlock(&head->lock);
+	spin_unlock(&delayed_refs->lock);
+
+	btrfs_delayed_ref_unlock(head);
+	btrfs_put_delayed_ref_head(head);
+}
+
+static void delete_delayed_ref_node(struct btrfs_delayed_ref_head *head,
+				    struct btrfs_delayed_ref_node *node)
+{
+	rb_erase_cached(&node->ref_node, &head->ref_tree);
+	RB_CLEAR_NODE(&node->ref_node);
+	if (!list_empty(&node->add_list))
+		list_del_init(&node->add_list);
+	btrfs_put_delayed_ref(node);
+}
+
+static int validate_ref_head(struct btrfs_delayed_ref_head *head,
+			     struct ref_head_check *check)
+{
+	if (head->bytenr != check->bytenr) {
+		test_err("invalid bytenr have: %llu want: %llu", head->bytenr,
+			 check->bytenr);
+		return -EINVAL;
+	}
+
+	if (head->num_bytes != check->num_bytes) {
+		test_err("invalid num_bytes have: %llu want: %llu",
+			 head->num_bytes, check->num_bytes);
+		return -EINVAL;
+	}
+
+	if (head->ref_mod != check->ref_mod) {
+		test_err("invalid ref_mod have: %d want: %d", head->ref_mod,
+			 check->ref_mod);
+		return -EINVAL;
+	}
+
+	if (head->total_ref_mod != check->total_ref_mod) {
+		test_err("invalid total_ref_mod have: %d want: %d",
+			 head->total_ref_mod, check->total_ref_mod);
+		return -EINVAL;
+	}
+
+	if (head->must_insert_reserved != check->must_insert) {
+		test_err("invalid must_insert have: %d want: %d",
+			 head->must_insert_reserved, check->must_insert);
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
+static int validate_ref_node(struct btrfs_delayed_ref_node *node,
+			     struct ref_node_check *check)
+{
+	if (node->bytenr != check->bytenr) {
+		test_err("invalid bytenr have: %llu want: %llu", node->bytenr,
+			 check->bytenr);
+		return -EINVAL;
+	}
+
+	if (node->num_bytes != check->num_bytes) {
+		test_err("invalid num_bytes have: %llu want: %llu",
+			 node->num_bytes, check->num_bytes);
+		return -EINVAL;
+	}
+
+	if (node->ref_mod != check->ref_mod) {
+		test_err("invalid ref_mod have: %d want: %d", node->ref_mod,
+			 check->ref_mod);
+		return -EINVAL;
+	}
+
+	if (node->action != check->action) {
+		test_err("invalid action have: %d want: %d", node->action,
+			 check->action);
+		return -EINVAL;
+	}
+
+	if (node->parent != check->parent) {
+		test_err("invalid parent have: %llu want: %llu", node->parent,
+			 check->parent);
+		return -EINVAL;
+	}
+
+	if (node->ref_root != check->root) {
+		test_err("invalid root have: %llu want: %llu", node->ref_root,
+			 check->root);
+		return -EINVAL;
+	}
+
+	if (node->type != check->type) {
+		test_err("invalid type have: %d want: %d", node->type,
+			 check->type);
+		return -EINVAL;
+	}
+
+	if (btrfs_delayed_ref_owner(node) != check->owner) {
+		test_err("invalid owner have: %llu want: %llu",
+			 btrfs_delayed_ref_owner(node), check->owner);
+		return -EINVAL;
+	}
+
+	if (btrfs_delayed_ref_offset(node) != check->offset) {
+		test_err("invalid offset have: %llu want: %llu",
+			 btrfs_delayed_ref_offset(node), check->offset);
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
+static int simple_test(struct btrfs_trans_handle *trans,
+		       struct ref_head_check *head_check,
+		       struct ref_node_check *node_check)
+{
+	struct btrfs_delayed_ref_root *delayed_refs =
+		&trans->transaction->delayed_refs;
+	struct btrfs_fs_info *fs_info = trans->fs_info;
+	struct btrfs_delayed_ref_head *head;
+	struct btrfs_delayed_ref_node *node;
+	struct btrfs_ref ref = {
+		.type = ref_type_from_disk_ref_type(node_check->type),
+		.action = node_check->action,
+		.parent = node_check->parent,
+		.ref_root = node_check->root,
+		.bytenr = node_check->bytenr,
+		.num_bytes = fs_info->nodesize,
+	};
+	int ret;
+
+	if (ref.type == BTRFS_REF_METADATA)
+		btrfs_init_tree_ref(&ref, node_check->owner, node_check->root,
+				    false);
+	else
+		btrfs_init_data_ref(&ref, node_check->owner, node_check->offset,
+				    node_check->root, true);
+
+	if (ref.type == BTRFS_REF_METADATA)
+		ret = btrfs_add_delayed_tree_ref(trans, &ref, NULL);
+	else
+		ret = btrfs_add_delayed_data_ref(trans, &ref, 0);
+	if (ret) {
+		test_err("failed ref action %d", ret);
+		return ret;
+	}
+
+	head = btrfs_select_ref_head(fs_info, delayed_refs);
+	if (IS_ERR_OR_NULL(head)) {
+		if (IS_ERR(head))
+			test_err("failed to select delayed ref head: %ld",
+				 PTR_ERR(head));
+		else
+			test_err("failed to find delayed ref head");
+		return -EINVAL;
+	}
+
+	ret = -EINVAL;
+	if (validate_ref_head(head, head_check))
+		goto out;
+
+	spin_lock(&head->lock);
+	node = btrfs_select_delayed_ref(head);
+	spin_unlock(&head->lock);
+	if (!node) {
+		test_err("failed to select delayed ref");
+		goto out;
+	}
+
+	if (validate_ref_node(node, node_check))
+		goto out;
+	ret = 0;
+out:
+	btrfs_unselect_ref_head(delayed_refs, head);
+	btrfs_destroy_delayed_refs(trans->transaction);
+	return ret;
+}
+
+/*
+ * These are simple tests, make sure that our btrfs_ref's get turned into the
+ * appropriate btrfs_delayed_ref_node based on their settings and action.
+ */
+static int simple_tests(struct btrfs_trans_handle *trans)
+{
+	struct btrfs_fs_info *fs_info = trans->fs_info;
+	struct ref_head_check head_check = {
+		.bytenr = FAKE_BYTENR,
+		.num_bytes = fs_info->nodesize,
+		.ref_mod = 1,
+		.total_ref_mod = 1,
+	};
+	struct ref_node_check node_check = {
+		.bytenr = FAKE_BYTENR,
+		.num_bytes = fs_info->nodesize,
+		.ref_mod = 1,
+		.action = BTRFS_ADD_DELAYED_REF,
+		.type = BTRFS_TREE_BLOCK_REF_KEY,
+		.parent = 0,
+		.root = FAKE_ROOT_OBJECTID,
+		.owner = FAKE_LEVEL,
+		.offset = 0,
+	};
+
+	if (simple_test(trans, &head_check, &node_check)) {
+		test_err("single add tree block failed");
+		return -EINVAL;
+	}
+
+	node_check.type = BTRFS_EXTENT_DATA_REF_KEY;
+	node_check.owner = FAKE_INO;
+	node_check.offset = FAKE_FILE_OFFSET;
+
+	if (simple_test(trans, &head_check, &node_check)) {
+		test_err("single add extent data failed");
+		return -EINVAL;
+	}
+
+	node_check.parent = FAKE_PARENT;
+	node_check.type = BTRFS_SHARED_BLOCK_REF_KEY;
+	node_check.owner = FAKE_LEVEL;
+	node_check.offset = 0;
+
+	if (simple_test(trans, &head_check, &node_check)) {
+		test_err("single add shared block failed");
+		return -EINVAL;
+	}
+
+	node_check.type = BTRFS_SHARED_DATA_REF_KEY;
+	node_check.owner = FAKE_INO;
+	node_check.offset = FAKE_FILE_OFFSET;
+
+	if (simple_test(trans, &head_check, &node_check)) {
+		test_err("single add shared data failed");
+		return -EINVAL;
+	}
+
+	head_check.ref_mod = -1;
+	head_check.total_ref_mod = -1;
+	node_check.action = BTRFS_DROP_DELAYED_REF;
+	node_check.type = BTRFS_TREE_BLOCK_REF_KEY;
+	node_check.owner = FAKE_LEVEL;
+	node_check.offset = 0;
+	node_check.parent = 0;
+
+	if (simple_test(trans, &head_check, &node_check)) {
+		test_err("single drop tree block failed");
+		return -EINVAL;
+	}
+
+	node_check.type = BTRFS_EXTENT_DATA_REF_KEY;
+	node_check.owner = FAKE_INO;
+	node_check.offset = FAKE_FILE_OFFSET;
+
+	if (simple_test(trans, &head_check, &node_check)) {
+		test_err("single drop extent data failed");
+		return -EINVAL;
+	}
+
+	node_check.parent = FAKE_PARENT;
+	node_check.type = BTRFS_SHARED_BLOCK_REF_KEY;
+	node_check.owner = FAKE_LEVEL;
+	node_check.offset = 0;
+	if (simple_test(trans, &head_check, &node_check)) {
+		test_err("single drop shared block failed");
+		return -EINVAL;
+	}
+
+	node_check.type = BTRFS_SHARED_DATA_REF_KEY;
+	node_check.owner = FAKE_INO;
+	node_check.offset = FAKE_FILE_OFFSET;
+	if (simple_test(trans, &head_check, &node_check)) {
+		test_err("single drop shared data failed");
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
+/*
+ * Merge tests, validate that we do delayed ref merging properly, the ref counts
+ * all end up properly, and delayed refs are deleted once they're no longer
+ * needed.
+ */
+static int merge_tests(struct btrfs_trans_handle *trans,
+		       enum btrfs_ref_type type)
+{
+	struct btrfs_fs_info *fs_info = trans->fs_info;
+	struct btrfs_delayed_ref_head *head = NULL;
+	struct btrfs_delayed_ref_node *node;
+	struct btrfs_ref ref = {
+		.type = type,
+		.action = BTRFS_ADD_DELAYED_REF,
+		.parent = 0,
+		.ref_root = FAKE_ROOT_OBJECTID,
+		.bytenr = FAKE_BYTENR,
+		.num_bytes = fs_info->nodesize,
+	};
+	struct ref_head_check head_check = {
+		.bytenr = FAKE_BYTENR,
+		.num_bytes = fs_info->nodesize,
+		.ref_mod = 0,
+		.total_ref_mod = 0,
+	};
+	struct ref_node_check node_check = {
+		.bytenr = FAKE_BYTENR,
+		.num_bytes = fs_info->nodesize,
+		.ref_mod = 2,
+		.action = BTRFS_ADD_DELAYED_REF,
+		.parent = 0,
+		.root = FAKE_ROOT_OBJECTID,
+	};
+	int ret;
+
+	/*
+	 * First add a ref and then drop it, make sure we get a head ref with a
+	 * 0 total ref mod and no nodes.
+	 */
+	if (type == BTRFS_REF_METADATA) {
+		node_check.type = BTRFS_TREE_BLOCK_REF_KEY;
+		node_check.owner = FAKE_LEVEL;
+		btrfs_init_tree_ref(&ref, FAKE_LEVEL, FAKE_ROOT_OBJECTID, false);
+	} else {
+		node_check.type = BTRFS_EXTENT_DATA_REF_KEY;
+		node_check.owner = FAKE_INO;
+		node_check.offset = FAKE_FILE_OFFSET;
+		btrfs_init_data_ref(&ref, FAKE_INO, FAKE_FILE_OFFSET,
+				    FAKE_ROOT_OBJECTID, true);
+	}
+
+	if (type == BTRFS_REF_METADATA)
+		ret = btrfs_add_delayed_tree_ref(trans, &ref, NULL);
+	else
+		ret = btrfs_add_delayed_data_ref(trans, &ref, 0);
+	if (ret) {
+		test_err("failed ref action %d", ret);
+		return ret;
+	}
+
+	ref.action = BTRFS_DROP_DELAYED_REF;
+	if (type == BTRFS_REF_METADATA)
+		ret = btrfs_add_delayed_tree_ref(trans, &ref, NULL);
+	else
+		ret = btrfs_add_delayed_data_ref(trans, &ref, 0);
+	if (ret) {
+		test_err("failed ref action %d", ret);
+		goto out;
+	}
+
+	head = btrfs_select_ref_head(fs_info, &trans->transaction->delayed_refs);
+	if (IS_ERR_OR_NULL(head)) {
+		if (IS_ERR(head))
+			test_err("failed to select delayed ref head: %ld",
+				 PTR_ERR(head));
+		else
+			test_err("failed to find delayed ref head");
+		goto out;
+	}
+
+	ret = -EINVAL;
+	if (validate_ref_head(head, &head_check)) {
+		test_err("single add and drop failed");
+		goto out;
+	}
+
+	spin_lock(&head->lock);
+	node = btrfs_select_delayed_ref(head);
+	spin_unlock(&head->lock);
+	if (node) {
+		test_err("found node when none should exist");
+		goto out;
+	}
+
+	delete_delayed_ref_head(trans, head);
+	head = NULL;
+
+	/*
+	 * Add a ref, then add another ref, make sure we get a head ref with a
+	 * 2 total ref mod and 1 node.
+	 */
+	ref.action = BTRFS_ADD_DELAYED_REF;
+	if (type == BTRFS_REF_METADATA)
+		ret = btrfs_add_delayed_tree_ref(trans, &ref, NULL);
+	else
+		ret = btrfs_add_delayed_data_ref(trans, &ref, 0);
+	if (ret) {
+		test_err("failed ref action %d", ret);
+		goto out;
+	}
+
+	if (type == BTRFS_REF_METADATA)
+		ret = btrfs_add_delayed_tree_ref(trans, &ref, NULL);
+	else
+		ret = btrfs_add_delayed_data_ref(trans, &ref, 0);
+	if (ret) {
+		test_err("failed ref action %d", ret);
+		goto out;
+	}
+
+	head = btrfs_select_ref_head(fs_info, &trans->transaction->delayed_refs);
+	if (IS_ERR_OR_NULL(head)) {
+		if (IS_ERR(head))
+			test_err("failed to select delayed ref head: %ld",
+				 PTR_ERR(head));
+		else
+			test_err("failed to find delayed ref head");
+		goto out;
+	}
+
+	head_check.ref_mod = 2;
+	head_check.total_ref_mod = 2;
+	ret = -EINVAL;
+	if (validate_ref_head(head, &head_check)) {
+		test_err("double add failed");
+		goto out;
+	}
+
+	spin_lock(&head->lock);
+	node = btrfs_select_delayed_ref(head);
+	spin_unlock(&head->lock);
+	if (!node) {
+		test_err("failed to select delayed ref");
+		goto out;
+	}
+
+	if (validate_ref_node(node, &node_check)) {
+		test_err("node check failed");
+		goto out;
+	}
+
+	delete_delayed_ref_node(head, node);
+
+	spin_lock(&head->lock);
+	node = btrfs_select_delayed_ref(head);
+	spin_unlock(&head->lock);
+	if (node) {
+		test_err("found node when none should exist");
+		goto out;
+	}
+	delete_delayed_ref_head(trans, head);
+	head = NULL;
+
+	/* Add two drop refs, make sure they are merged properly. */
+	ref.action = BTRFS_DROP_DELAYED_REF;
+	if (type == BTRFS_REF_METADATA)
+		ret = btrfs_add_delayed_tree_ref(trans, &ref, NULL);
+	else
+		ret = btrfs_add_delayed_data_ref(trans, &ref, 0);
+	if (ret) {
+		test_err("failed ref action %d", ret);
+		goto out;
+	}
+
+	if (type == BTRFS_REF_METADATA)
+		ret = btrfs_add_delayed_tree_ref(trans, &ref, NULL);
+	else
+		ret = btrfs_add_delayed_data_ref(trans, &ref, 0);
+	if (ret) {
+		test_err("failed ref action %d", ret);
+		goto out;
+	}
+
+	head = btrfs_select_ref_head(fs_info, &trans->transaction->delayed_refs);
+	if (IS_ERR_OR_NULL(head)) {
+		if (IS_ERR(head))
+			test_err("failed to select delayed ref head: %ld",
+				 PTR_ERR(head));
+		else
+			test_err("failed to find delayed ref head");
+		goto out;
+	}
+
+	head_check.ref_mod = -2;
+	head_check.total_ref_mod = -2;
+	ret = -EINVAL;
+	if (validate_ref_head(head, &head_check)) {
+		test_err("double drop failed");
+		goto out;
+	}
+
+	node_check.action = BTRFS_DROP_DELAYED_REF;
+	spin_lock(&head->lock);
+	node = btrfs_select_delayed_ref(head);
+	spin_unlock(&head->lock);
+	if (!node) {
+		test_err("failed to select delayed ref");
+		goto out;
+	}
+
+	if (validate_ref_node(node, &node_check)) {
+		test_err("node check failed");
+		goto out;
+	}
+
+	delete_delayed_ref_node(head, node);
+
+	spin_lock(&head->lock);
+	node = btrfs_select_delayed_ref(head);
+	spin_unlock(&head->lock);
+	if (node) {
+		test_err("found node when none should exist");
+		goto out;
+	}
+	delete_delayed_ref_head(trans, head);
+	head = NULL;
+
+	/* Add multiple refs, then drop until we go negative again. */
+	ref.action = BTRFS_ADD_DELAYED_REF;
+	for (int i = 0; i < 10; i++) {
+		if (type == BTRFS_REF_METADATA)
+			ret = btrfs_add_delayed_tree_ref(trans, &ref, NULL);
+		else
+			ret = btrfs_add_delayed_data_ref(trans, &ref, 0);
+		if (ret) {
+			test_err("failed ref action %d", ret);
+			goto out;
+		}
+	}
+
+	ref.action = BTRFS_DROP_DELAYED_REF;
+	for (int i = 0; i < 12; i++) {
+		if (type == BTRFS_REF_METADATA)
+			ret = btrfs_add_delayed_tree_ref(trans, &ref, NULL);
+		else
+			ret = btrfs_add_delayed_data_ref(trans, &ref, 0);
+		if (ret) {
+			test_err("failed ref action %d", ret);
+			goto out;
+		}
+	}
+
+	head = btrfs_select_ref_head(fs_info, &trans->transaction->delayed_refs);
+	if (IS_ERR_OR_NULL(head)) {
+		if (IS_ERR(head))
+			test_err("failed to select delayed ref head: %ld",
+				 PTR_ERR(head));
+		else
+			test_err("failed to find delayed ref head");
+		ret = -EINVAL;
+		goto out;
+	}
+
+	head_check.ref_mod = -2;
+	head_check.total_ref_mod = -2;
+	ret = -EINVAL;
+	if (validate_ref_head(head, &head_check)) {
+		test_err("double drop failed");
+		goto out;
+	}
+
+	spin_lock(&head->lock);
+	node = btrfs_select_delayed_ref(head);
+	spin_unlock(&head->lock);
+	if (!node) {
+		test_err("failed to select delayed ref");
+		goto out;
+	}
+
+	if (validate_ref_node(node, &node_check)) {
+		test_err("node check failed");
+		goto out;
+	}
+
+	delete_delayed_ref_node(head, node);
+
+	spin_lock(&head->lock);
+	node = btrfs_select_delayed_ref(head);
+	spin_unlock(&head->lock);
+	if (node) {
+		test_err("found node when none should exist");
+		goto out;
+	}
+
+	delete_delayed_ref_head(trans, head);
+	head = NULL;
+
+	/* Drop multiple refs, then add until we go positive again. */
+	ref.action = BTRFS_DROP_DELAYED_REF;
+	for (int i = 0; i < 10; i++) {
+		if (type == BTRFS_REF_METADATA)
+			ret = btrfs_add_delayed_tree_ref(trans, &ref, NULL);
+		else
+			ret = btrfs_add_delayed_data_ref(trans, &ref, 0);
+		if (ret) {
+			test_err("failed ref action %d", ret);
+			goto out;
+		}
+	}
+
+	ref.action = BTRFS_ADD_DELAYED_REF;
+	for (int i = 0; i < 12; i++) {
+		if (type == BTRFS_REF_METADATA)
+			ret = btrfs_add_delayed_tree_ref(trans, &ref, NULL);
+		else
+			ret = btrfs_add_delayed_data_ref(trans, &ref, 0);
+		if (ret) {
+			test_err("failed ref action %d", ret);
+			goto out;
+		}
+	}
+
+	head = btrfs_select_ref_head(fs_info, &trans->transaction->delayed_refs);
+	if (IS_ERR_OR_NULL(head)) {
+		if (IS_ERR(head))
+			test_err("failed to select delayed ref head: %ld",
+				 PTR_ERR(head));
+		else
+			test_err("failed to find delayed ref head");
+		ret = -EINVAL;
+		goto out;
+	}
+
+	head_check.ref_mod = 2;
+	head_check.total_ref_mod = 2;
+	ret = -EINVAL;
+	if (validate_ref_head(head, &head_check)) {
+		test_err("add and drop to positive failed");
+		goto out;
+	}
+
+	node_check.action = BTRFS_ADD_DELAYED_REF;
+	spin_lock(&head->lock);
+	node = btrfs_select_delayed_ref(head);
+	spin_unlock(&head->lock);
+	if (!node) {
+		test_err("failed to select delayed ref");
+		goto out;
+	}
+
+	if (validate_ref_node(node, &node_check)) {
+		test_err("node check failed");
+		goto out;
+	}
+
+	delete_delayed_ref_node(head, node);
+
+	spin_lock(&head->lock);
+	node = btrfs_select_delayed_ref(head);
+	spin_unlock(&head->lock);
+	if (node) {
+		test_err("found node when none should exist");
+		goto out;
+	}
+	delete_delayed_ref_head(trans, head);
+	head = NULL;
+
+	/*
+	 * Add a bunch of refs with different roots and parents, then drop them
+	 * all, make sure everything is properly merged.
+	 */
+	ref.action = BTRFS_ADD_DELAYED_REF;
+	for (int i = 0; i < 50; i++) {
+		if (!(i % 2)) {
+			ref.parent = 0;
+			ref.ref_root = FAKE_ROOT_OBJECTID + i;
+		} else {
+			ref.parent = FAKE_PARENT + (i * fs_info->nodesize);
+		}
+		if (type == BTRFS_REF_METADATA)
+			ret = btrfs_add_delayed_tree_ref(trans, &ref, NULL);
+		else
+			ret = btrfs_add_delayed_data_ref(trans, &ref, 0);
+		if (ret) {
+			test_err("failed ref action %d", ret);
+			goto out;
+		}
+	}
+
+	ref.action = BTRFS_DROP_DELAYED_REF;
+	for (int i = 0; i < 50; i++) {
+		if (!(i % 2)) {
+			ref.parent = 0;
+			ref.ref_root = FAKE_ROOT_OBJECTID + i;
+		} else {
+			ref.parent = FAKE_PARENT + (i * fs_info->nodesize);
+		}
+		if (type == BTRFS_REF_METADATA)
+			ret = btrfs_add_delayed_tree_ref(trans, &ref, NULL);
+		else
+			ret = btrfs_add_delayed_data_ref(trans, &ref, 0);
+		if (ret) {
+			test_err("failed ref action %d", ret);
+			goto out;
+		}
+	}
+
+	head = btrfs_select_ref_head(fs_info, &trans->transaction->delayed_refs);
+	if (IS_ERR_OR_NULL(head)) {
+		if (IS_ERR(head))
+			test_err("failed to select delayed ref head: %ld",
+				 PTR_ERR(head));
+		else
+			test_err("failed to find delayed ref head");
+		ret = -EINVAL;
+		goto out;
+	}
+
+	head_check.ref_mod = 0;
+	head_check.total_ref_mod = 0;
+	ret = -EINVAL;
+	if (validate_ref_head(head, &head_check)) {
+		test_err("add and drop multiple failed");
+		goto out;
+	}
+
+	spin_lock(&head->lock);
+	node = btrfs_select_delayed_ref(head);
+	spin_unlock(&head->lock);
+	if (node) {
+		test_err("found node when none should exist");
+		goto out;
+	}
+	ret = 0;
+out:
+	if (!IS_ERR_OR_NULL(head))
+		btrfs_unselect_ref_head(&trans->transaction->delayed_refs, head);
+	btrfs_destroy_delayed_refs(trans->transaction);
+	return ret;
+}
+
+/*
+ * Basic test to validate we always get the add operations first followed by any
+ * delete operations.
+ */
+static int select_delayed_refs_test(struct btrfs_trans_handle *trans)
+{
+	struct btrfs_delayed_ref_root *delayed_refs =
+		&trans->transaction->delayed_refs;
+	struct btrfs_fs_info *fs_info = trans->fs_info;
+	struct btrfs_delayed_ref_head *head = NULL;
+	struct btrfs_delayed_ref_node *node;
+	struct btrfs_ref ref = {
+		.type = BTRFS_REF_METADATA,
+		.action = BTRFS_DROP_DELAYED_REF,
+		.parent = 0,
+		.ref_root = FAKE_ROOT_OBJECTID,
+		.bytenr = FAKE_BYTENR,
+		.num_bytes = fs_info->nodesize,
+	};
+	struct ref_head_check head_check = {
+		.bytenr = FAKE_BYTENR,
+		.num_bytes = fs_info->nodesize,
+		.ref_mod = 0,
+		.total_ref_mod = 0,
+	};
+	struct ref_node_check node_check = {
+		.bytenr = FAKE_BYTENR,
+		.num_bytes = fs_info->nodesize,
+		.ref_mod = 1,
+		.action = BTRFS_ADD_DELAYED_REF,
+		.type = BTRFS_TREE_BLOCK_REF_KEY,
+		.parent = 0,
+		.owner = FAKE_LEVEL,
+		.offset = 0,
+	};
+	int ret;
+
+	/* Add the drop first. */
+	btrfs_init_tree_ref(&ref, FAKE_LEVEL, FAKE_ROOT_OBJECTID, false);
+	ret = btrfs_add_delayed_tree_ref(trans, &ref, NULL);
+	if (ret) {
+		test_err("failed ref action %d", ret);
+		return ret;
+	}
+
+	/*
+	 * Now add the add, and make it a different root so it's logically later
+	 * in the rb tree.
+	 */
+	ref.action = BTRFS_ADD_DELAYED_REF;
+	ref.ref_root = FAKE_ROOT_OBJECTID + 1;
+	ret = btrfs_add_delayed_tree_ref(trans, &ref, NULL);
+	if (ret) {
+		test_err("failed ref action %d", ret);
+		goto out;
+	}
+
+	head = btrfs_select_ref_head(fs_info, delayed_refs);
+	if (IS_ERR_OR_NULL(head)) {
+		if (IS_ERR(head))
+			test_err("failed to select delayed ref head: %ld",
+				 PTR_ERR(head));
+		else
+			test_err("failed to find delayed ref head");
+		ret = -EINVAL;
+		head = NULL;
+		goto out;
+	}
+
+	ret = -EINVAL;
+	if (validate_ref_head(head, &head_check)) {
+		test_err("head check failed");
+		goto out;
+	}
+
+	spin_lock(&head->lock);
+	node = btrfs_select_delayed_ref(head);
+	spin_unlock(&head->lock);
+	if (!node) {
+		test_err("failed to select delayed ref");
+		goto out;
+	}
+
+	node_check.root = FAKE_ROOT_OBJECTID + 1;
+	if (validate_ref_node(node, &node_check)) {
+		test_err("node check failed");
+		goto out;
+	}
+	delete_delayed_ref_node(head, node);
+
+	spin_lock(&head->lock);
+	node = btrfs_select_delayed_ref(head);
+	spin_unlock(&head->lock);
+	if (!node) {
+		test_err("failed to select delayed ref");
+		goto out;
+	}
+
+	node_check.action = BTRFS_DROP_DELAYED_REF;
+	node_check.root = FAKE_ROOT_OBJECTID;
+	if (validate_ref_node(node, &node_check)) {
+		test_err("node check failed");
+		goto out;
+	}
+	delete_delayed_ref_node(head, node);
+	delete_delayed_ref_head(trans, head);
+	head = NULL;
+
+	/*
+	 * Now we're going to do the same thing, but we're going to have an add
+	 * that gets deleted because of a merge, and make sure we still have
+	 * another add in place.
+	 */
+	ref.action = BTRFS_DROP_DELAYED_REF;
+	ref.ref_root = FAKE_ROOT_OBJECTID;
+	ret = btrfs_add_delayed_tree_ref(trans, &ref, NULL);
+	if (ret) {
+		test_err("failed ref action %d", ret);
+		goto out;
+	}
+
+	ref.action = BTRFS_ADD_DELAYED_REF;
+	ref.ref_root = FAKE_ROOT_OBJECTID + 1;
+	ret = btrfs_add_delayed_tree_ref(trans, &ref, NULL);
+	if (ret) {
+		test_err("failed ref action %d", ret);
+		goto out;
+	}
+
+	ref.action = BTRFS_DROP_DELAYED_REF;
+	ret = btrfs_add_delayed_tree_ref(trans, &ref, NULL);
+	if (ret) {
+		test_err("failed ref action %d", ret);
+		goto out;
+	}
+
+	ref.action = BTRFS_ADD_DELAYED_REF;
+	ref.ref_root = FAKE_ROOT_OBJECTID + 2;
+	ret = btrfs_add_delayed_tree_ref(trans, &ref, NULL);
+	if (ret) {
+		test_err("failed ref action %d", ret);
+		goto out;
+	}
+
+	head = btrfs_select_ref_head(fs_info, delayed_refs);
+	if (IS_ERR_OR_NULL(head)) {
+		if (IS_ERR(head))
+			test_err("failed to select delayed ref head: %ld",
+				 PTR_ERR(head));
+		else
+			test_err("failed to find delayed ref head");
+		ret = -EINVAL;
+		head = NULL;
+		goto out;
+	}
+
+	ret = -EINVAL;
+	if (validate_ref_head(head, &head_check)) {
+		test_err("head check failed");
+		goto out;
+	}
+
+	spin_lock(&head->lock);
+	node = btrfs_select_delayed_ref(head);
+	spin_unlock(&head->lock);
+	if (!node) {
+		test_err("failed to select delayed ref");
+		goto out;
+	}
+
+	node_check.action = BTRFS_ADD_DELAYED_REF;
+	node_check.root = FAKE_ROOT_OBJECTID + 2;
+	if (validate_ref_node(node, &node_check)) {
+		test_err("node check failed");
+		goto out;
+	}
+	delete_delayed_ref_node(head, node);
+
+	spin_lock(&head->lock);
+	node = btrfs_select_delayed_ref(head);
+	spin_unlock(&head->lock);
+	if (!node) {
+		test_err("failed to select delayed ref");
+		goto out;
+	}
+
+	node_check.action = BTRFS_DROP_DELAYED_REF;
+	node_check.root = FAKE_ROOT_OBJECTID;
+	if (validate_ref_node(node, &node_check)) {
+		test_err("node check failed");
+		goto out;
+	}
+	delete_delayed_ref_node(head, node);
+	ret = 0;
+out:
+	if (head)
+		btrfs_unselect_ref_head(delayed_refs, head);
+	btrfs_destroy_delayed_refs(trans->transaction);
+	return ret;
+}
+
+int btrfs_test_delayed_refs(u32 sectorsize, u32 nodesize)
+{
+	struct btrfs_transaction *transaction;
+	struct btrfs_trans_handle trans;
+	struct btrfs_fs_info *fs_info;
+	int ret;
+
+	test_msg("running delayed refs tests");
+
+	fs_info = btrfs_alloc_dummy_fs_info(nodesize, sectorsize);
+	if (!fs_info) {
+		test_std_err(TEST_ALLOC_FS_INFO);
+		return -ENOMEM;
+	}
+	transaction = kmalloc(sizeof(*transaction), GFP_KERNEL);
+	if (!transaction) {
+		test_std_err(TEST_ALLOC_TRANSACTION);
+		ret = -ENOMEM;
+		goto out_free_fs_info;
+	}
+	btrfs_init_dummy_trans(&trans, fs_info);
+	btrfs_init_dummy_transaction(transaction, fs_info);
+	trans.transaction = transaction;
+
+	ret = simple_tests(&trans);
+	if (!ret) {
+		test_msg("running delayed refs merg tests on metadata refs");
+		ret = merge_tests(&trans, BTRFS_REF_METADATA);
+	}
+
+	if (!ret) {
+		test_msg("running delayed refs merg tests on data refs");
+		ret = merge_tests(&trans, BTRFS_REF_DATA);
+	}
+
+	if (!ret)
+		ret = select_delayed_refs_test(&trans);
+
+out_free_fs_info:
+	btrfs_free_dummy_fs_info(fs_info);
+	return ret;
+}
diff --git a/fs/btrfs/tests/raid-stripe-tree-tests.c b/fs/btrfs/tests/raid-stripe-tree-tests.c
index 30f17eb..a7bc58a 100644
--- a/fs/btrfs/tests/raid-stripe-tree-tests.c
+++ b/fs/btrfs/tests/raid-stripe-tree-tests.c
@@ -14,6 +14,8 @@
 #define RST_TEST_NUM_DEVICES	(2)
 #define RST_TEST_RAID1_TYPE	(BTRFS_BLOCK_GROUP_DATA | BTRFS_BLOCK_GROUP_RAID1)
 
+#define SZ_48K (SZ_32K + SZ_16K)
+
 typedef int (*test_func_t)(struct btrfs_trans_handle *trans);
 
 static struct btrfs_device *btrfs_device_by_devid(struct btrfs_fs_devices *fs_devices,
@@ -30,6 +32,613 @@ static struct btrfs_device *btrfs_device_by_devid(struct btrfs_fs_devices *fs_de
 }
 
 /*
+ * Test creating a range of three extents and then punch a hole in the middle,
+ * deleting all of the middle extents and partially deleting the "book ends".
+ */
+static int test_punch_hole_3extents(struct btrfs_trans_handle *trans)
+{
+	struct btrfs_fs_info *fs_info = trans->fs_info;
+	struct btrfs_io_context *bioc;
+	struct btrfs_io_stripe io_stripe = { 0 };
+	u64 map_type = RST_TEST_RAID1_TYPE;
+	u64 logical1 = SZ_1M;
+	u64 len1 = SZ_1M;
+	u64 logical2 = logical1 + len1;
+	u64 len2 = SZ_1M;
+	u64 logical3 = logical2 + len2;
+	u64 len3 = SZ_1M;
+	u64 hole_start = logical1 + SZ_256K;
+	u64 hole_len = SZ_2M;
+	int ret;
+
+	bioc = alloc_btrfs_io_context(fs_info, logical1, RST_TEST_NUM_DEVICES);
+	if (!bioc) {
+		test_std_err(TEST_ALLOC_IO_CONTEXT);
+		ret = -ENOMEM;
+		goto out;
+	}
+
+	io_stripe.dev = btrfs_device_by_devid(fs_info->fs_devices, 0);
+
+	/* Prepare for the test, 1st create 3 x 1M extents. */
+	bioc->map_type = map_type;
+	bioc->size = len1;
+
+	for (int i = 0; i < RST_TEST_NUM_DEVICES; i++) {
+		struct btrfs_io_stripe *stripe = &bioc->stripes[i];
+
+		stripe->dev = btrfs_device_by_devid(fs_info->fs_devices, i);
+		if (!stripe->dev) {
+			test_err("cannot find device with devid %d", i);
+			ret = -EINVAL;
+			goto out;
+		}
+
+		stripe->physical = logical1 + i * SZ_1G;
+	}
+
+	ret = btrfs_insert_one_raid_extent(trans, bioc);
+	if (ret) {
+		test_err("inserting RAID extent failed: %d", ret);
+		goto out;
+	}
+
+	bioc->logical = logical2;
+	bioc->size = len2;
+	for (int i = 0; i < RST_TEST_NUM_DEVICES; i++) {
+		struct btrfs_io_stripe *stripe = &bioc->stripes[i];
+
+		stripe->dev = btrfs_device_by_devid(fs_info->fs_devices, i);
+		if (!stripe->dev) {
+			test_err("cannot find device with devid %d", i);
+			ret = -EINVAL;
+			goto out;
+		}
+
+		stripe->physical = logical2 + i * SZ_1G;
+	}
+
+	ret = btrfs_insert_one_raid_extent(trans, bioc);
+	if (ret) {
+		test_err("inserting RAID extent failed: %d", ret);
+		goto out;
+	}
+
+	bioc->logical = logical3;
+	bioc->size = len3;
+	for (int i = 0; i < RST_TEST_NUM_DEVICES; i++) {
+		struct btrfs_io_stripe *stripe = &bioc->stripes[i];
+
+		stripe->dev = btrfs_device_by_devid(fs_info->fs_devices, i);
+		if (!stripe->dev) {
+			test_err("cannot find device with devid %d", i);
+			ret = -EINVAL;
+			goto out;
+		}
+
+		stripe->physical = logical3 + i * SZ_1G;
+	}
+
+	ret = btrfs_insert_one_raid_extent(trans, bioc);
+	if (ret) {
+		test_err("inserting RAID extent failed: %d", ret);
+		goto out;
+	}
+
+	/*
+	 * Delete a range starting at logical1 + 256K and 2M in length. Extent
+	 * 1 is truncated to 256k length, extent 2 is completely dropped and
+	 * extent 3 is moved 256K to the right.
+	 */
+	ret = btrfs_delete_raid_extent(trans, hole_start, hole_len);
+	if (ret) {
+		test_err("deleting RAID extent [%llu, %llu] failed",
+			 hole_start, hole_start + hole_len);
+		goto out;
+	}
+
+	/* Get the first extent and check its size. */
+	ret = btrfs_get_raid_extent_offset(fs_info, logical1, &len1, map_type,
+					   0, &io_stripe);
+	if (ret) {
+		test_err("lookup of RAID extent [%llu, %llu] failed",
+			 logical1, logical1 + len1);
+		goto out;
+	}
+
+	if (io_stripe.physical != logical1) {
+		test_err("invalid physical address, expected %llu, got %llu",
+			 logical1, io_stripe.physical);
+		ret = -EINVAL;
+		goto out;
+	}
+
+	if (len1 != SZ_256K) {
+		test_err("invalid stripe length, expected %llu, got %llu",
+			 (u64)SZ_256K, len1);
+		ret = -EINVAL;
+		goto out;
+	}
+
+	/* Get the second extent and check it's absent. */
+	ret = btrfs_get_raid_extent_offset(fs_info, logical2, &len2, map_type,
+					   0, &io_stripe);
+	if (ret != -ENODATA) {
+		test_err("lookup of RAID extent [%llu, %llu] succeeded should fail",
+			 logical2, logical2 + len2);
+		ret = -EINVAL;
+		goto out;
+	}
+
+	/* Get the third extent and check its size. */
+	logical3 += SZ_256K;
+	ret = btrfs_get_raid_extent_offset(fs_info, logical3, &len3, map_type,
+					   0, &io_stripe);
+	if (ret) {
+		test_err("lookup of RAID extent [%llu, %llu] failed",
+			 logical3, logical3 + len3);
+		goto out;
+	}
+
+	if (io_stripe.physical != logical3) {
+		test_err("invalid physical address, expected %llu, got %llu",
+			 logical3 + SZ_256K, io_stripe.physical);
+		ret = -EINVAL;
+		goto out;
+	}
+
+	if (len3 != SZ_1M - SZ_256K) {
+		test_err("invalid stripe length, expected %llu, got %llu",
+			 (u64)SZ_1M - SZ_256K, len3);
+		ret = -EINVAL;
+		goto out;
+	}
+
+	ret = btrfs_delete_raid_extent(trans, logical1, len1);
+	if (ret) {
+		test_err("deleting RAID extent [%llu, %llu] failed",
+			 logical1, logical1 + len1);
+		goto out;
+	}
+
+	ret = btrfs_delete_raid_extent(trans, logical3, len3);
+	if (ret) {
+		test_err("deleting RAID extent [%llu, %llu] failed",
+			 logical1, logical1 + len1);
+		goto out;
+	}
+
+out:
+	btrfs_put_bioc(bioc);
+	return ret;
+}
+
+static int test_delete_two_extents(struct btrfs_trans_handle *trans)
+{
+	struct btrfs_fs_info *fs_info = trans->fs_info;
+	struct btrfs_io_context *bioc;
+	struct btrfs_io_stripe io_stripe = { 0 };
+	u64 map_type = RST_TEST_RAID1_TYPE;
+	u64 logical1 = SZ_1M;
+	u64 len1 = SZ_1M;
+	u64 logical2 = logical1 + len1;
+	u64 len2 = SZ_1M;
+	u64 logical3 = logical2 + len2;
+	u64 len3 = SZ_1M;
+	int ret;
+
+	bioc = alloc_btrfs_io_context(fs_info, logical1, RST_TEST_NUM_DEVICES);
+	if (!bioc) {
+		test_std_err(TEST_ALLOC_IO_CONTEXT);
+		ret = -ENOMEM;
+		goto out;
+	}
+
+	io_stripe.dev = btrfs_device_by_devid(fs_info->fs_devices, 0);
+
+	/* Prepare for the test, 1st create 3 x 1M extents. */
+	bioc->map_type = map_type;
+	bioc->size = len1;
+
+	for (int i = 0; i < RST_TEST_NUM_DEVICES; i++) {
+		struct btrfs_io_stripe *stripe = &bioc->stripes[i];
+
+		stripe->dev = btrfs_device_by_devid(fs_info->fs_devices, i);
+		if (!stripe->dev) {
+			test_err("cannot find device with devid %d", i);
+			ret = -EINVAL;
+			goto out;
+		}
+
+		stripe->physical = logical1 + i * SZ_1G;
+	}
+
+	ret = btrfs_insert_one_raid_extent(trans, bioc);
+	if (ret) {
+		test_err("inserting RAID extent failed: %d", ret);
+		goto out;
+	}
+
+	bioc->logical = logical2;
+	bioc->size = len2;
+	for (int i = 0; i < RST_TEST_NUM_DEVICES; i++) {
+		struct btrfs_io_stripe *stripe = &bioc->stripes[i];
+
+		stripe->dev = btrfs_device_by_devid(fs_info->fs_devices, i);
+		if (!stripe->dev) {
+			test_err("cannot find device with devid %d", i);
+			ret = -EINVAL;
+			goto out;
+		}
+
+		stripe->physical = logical2 + i * SZ_1G;
+	}
+
+	ret = btrfs_insert_one_raid_extent(trans, bioc);
+	if (ret) {
+		test_err("inserting RAID extent failed: %d", ret);
+		goto out;
+	}
+
+	bioc->logical = logical3;
+	bioc->size = len3;
+	for (int i = 0; i < RST_TEST_NUM_DEVICES; i++) {
+		struct btrfs_io_stripe *stripe = &bioc->stripes[i];
+
+		stripe->dev = btrfs_device_by_devid(fs_info->fs_devices, i);
+		if (!stripe->dev) {
+			test_err("cannot find device with devid %d", i);
+			ret = -EINVAL;
+			goto out;
+		}
+
+		stripe->physical = logical3 + i * SZ_1G;
+	}
+
+	ret = btrfs_insert_one_raid_extent(trans, bioc);
+	if (ret) {
+		test_err("inserting RAID extent failed: %d", ret);
+		goto out;
+	}
+
+	/*
+	 * Delete a range starting at logical1 and 2M in length. Extents 1
+	 * and 2 are dropped and extent 3 is kept as is.
+	 */
+	ret = btrfs_delete_raid_extent(trans, logical1, len1 + len2);
+	if (ret) {
+		test_err("deleting RAID extent [%llu, %llu] failed",
+			 logical1, logical1 + len1 + len2);
+		goto out;
+	}
+
+	ret = btrfs_get_raid_extent_offset(fs_info, logical1, &len1, map_type,
+					   0, &io_stripe);
+	if (ret != -ENODATA) {
+		test_err("lookup of RAID extent [%llu, %llu] succeeded, should fail",
+			 logical1, len1);
+		goto out;
+	}
+
+	ret = btrfs_get_raid_extent_offset(fs_info, logical2, &len2, map_type,
+					   0, &io_stripe);
+	if (ret != -ENODATA) {
+		test_err("lookup of RAID extent [%llu, %llu] succeeded, should fail",
+			 logical2, len2);
+		goto out;
+	}
+
+	ret = btrfs_get_raid_extent_offset(fs_info, logical3, &len3, map_type,
+					   0, &io_stripe);
+	if (ret) {
+		test_err("lookup of RAID extent [%llu, %llu] failed",
+			 logical3, len3);
+		goto out;
+	}
+
+	if (io_stripe.physical != logical3) {
+		test_err("invalid physical address, expected %llu, got %llu",
+			 logical3, io_stripe.physical);
+		ret = -EINVAL;
+		goto out;
+	}
+
+	if (len3 != SZ_1M) {
+		test_err("invalid stripe length, expected %llu, got %llu",
+			 (u64)SZ_1M, len3);
+		ret = -EINVAL;
+		goto out;
+	}
+
+	ret = btrfs_delete_raid_extent(trans, logical3, len3);
+out:
+	btrfs_put_bioc(bioc);
+	return ret;
+}
+
+/* Test punching a hole into a single RAID stripe-extent. */
+static int test_punch_hole(struct btrfs_trans_handle *trans)
+{
+	struct btrfs_fs_info *fs_info = trans->fs_info;
+	struct btrfs_io_context *bioc;
+	struct btrfs_io_stripe io_stripe = { 0 };
+	u64 map_type = RST_TEST_RAID1_TYPE;
+	u64 logical1 = SZ_1M;
+	u64 hole_start = logical1 + SZ_32K;
+	u64 hole_len = SZ_64K;
+	u64 logical2 = hole_start + hole_len;
+	u64 len = SZ_1M;
+	u64 len1 = SZ_32K;
+	u64 len2 = len - len1 - hole_len;
+	int ret;
+
+	bioc = alloc_btrfs_io_context(fs_info, logical1, RST_TEST_NUM_DEVICES);
+	if (!bioc) {
+		test_std_err(TEST_ALLOC_IO_CONTEXT);
+		ret = -ENOMEM;
+		goto out;
+	}
+
+	io_stripe.dev = btrfs_device_by_devid(fs_info->fs_devices, 0);
+	bioc->map_type = map_type;
+	bioc->size = len;
+
+	for (int i = 0; i < RST_TEST_NUM_DEVICES; i++) {
+		struct btrfs_io_stripe *stripe = &bioc->stripes[i];
+
+		stripe->dev = btrfs_device_by_devid(fs_info->fs_devices, i);
+		if (!stripe->dev) {
+			test_err("cannot find device with devid %d", i);
+			ret = -EINVAL;
+			goto out;
+		}
+
+		stripe->physical = logical1 + i * SZ_1G;
+	}
+
+	ret = btrfs_insert_one_raid_extent(trans, bioc);
+	if (ret) {
+		test_err("inserting RAID extent failed: %d", ret);
+		goto out;
+	}
+
+	ret = btrfs_get_raid_extent_offset(fs_info, logical1, &len, map_type, 0,
+					   &io_stripe);
+	if (ret) {
+		test_err("lookup of RAID extent [%llu, %llu] failed", logical1,
+			 logical1 + len);
+		goto out;
+	}
+
+	if (io_stripe.physical != logical1) {
+		test_err("invalid physical address, expected %llu got %llu",
+			 logical1, io_stripe.physical);
+		ret = -EINVAL;
+		goto out;
+	}
+
+	if (len != SZ_1M) {
+		test_err("invalid stripe length, expected %llu got %llu",
+			 (u64)SZ_1M, len);
+		ret = -EINVAL;
+		goto out;
+	}
+
+	ret = btrfs_delete_raid_extent(trans, hole_start, hole_len);
+	if (ret) {
+		test_err("deleting RAID extent [%llu, %llu] failed",
+			 hole_start, hole_start + hole_len);
+		goto out;
+	}
+
+	ret = btrfs_get_raid_extent_offset(fs_info, logical1, &len1, map_type,
+					   0, &io_stripe);
+	if (ret) {
+		test_err("lookup of RAID extent [%llu, %llu] failed",
+			 logical1, logical1 + len1);
+		goto out;
+	}
+
+	if (io_stripe.physical != logical1) {
+		test_err("invalid physical address, expected %llu, got %llu",
+			 logical1, io_stripe.physical);
+		ret = -EINVAL;
+		goto out;
+	}
+
+	if (len1 != SZ_32K) {
+		test_err("invalid stripe length, expected %llu, got %llu",
+			 (u64)SZ_32K, len1);
+		ret = -EINVAL;
+		goto out;
+	}
+
+	ret = btrfs_get_raid_extent_offset(fs_info, logical2, &len2, map_type,
+					   0, &io_stripe);
+	if (ret) {
+		test_err("lookup of RAID extent [%llu, %llu] failed", logical2,
+			 logical2 + len2);
+		goto out;
+	}
+
+	if (io_stripe.physical != logical2) {
+		test_err("invalid physical address, expected %llu, got %llu",
+			 logical2, io_stripe.physical);
+		ret = -EINVAL;
+		goto out;
+	}
+
+	if (len2 != len - len1 - hole_len) {
+		test_err("invalid length, expected %llu, got %llu",
+			 len - len1 - hole_len, len2);
+		ret = -EINVAL;
+		goto out;
+	}
+
+	/* Check for the absence of the hole. */
+	ret = btrfs_get_raid_extent_offset(fs_info, hole_start, &hole_len,
+					   map_type, 0, &io_stripe);
+	if (ret != -ENODATA) {
+		ret = -EINVAL;
+		test_err("lookup of RAID extent [%llu, %llu] succeeded, should fail",
+			 hole_start, hole_start + SZ_64K);
+		goto out;
+	}
+
+	ret = btrfs_delete_raid_extent(trans, logical1, len1);
+	if (ret)
+		goto out;
+
+	ret = btrfs_delete_raid_extent(trans, logical2, len2);
+out:
+	btrfs_put_bioc(bioc);
+	return ret;
+}
+
+/*
+ * Test a 1M RST write that spans two adjacent RST items on disk and then
+ * delete a portion starting in the first item and spanning into the second
+ * item. This is similar to test_front_delete(), but spanning multiple items.
+ */
+static int test_front_delete_prev_item(struct btrfs_trans_handle *trans)
+{
+	struct btrfs_fs_info *fs_info = trans->fs_info;
+	struct btrfs_io_context *bioc;
+	struct btrfs_io_stripe io_stripe = { 0 };
+	u64 map_type = RST_TEST_RAID1_TYPE;
+	u64 logical1 = SZ_1M;
+	u64 logical2 = SZ_2M;
+	u64 len = SZ_1M;
+	int ret;
+
+	bioc = alloc_btrfs_io_context(fs_info, logical1, RST_TEST_NUM_DEVICES);
+	if (!bioc) {
+		test_std_err(TEST_ALLOC_IO_CONTEXT);
+		ret = -ENOMEM;
+		goto out;
+	}
+
+	io_stripe.dev = btrfs_device_by_devid(fs_info->fs_devices, 0);
+	bioc->map_type = map_type;
+	bioc->size = len;
+
+	/* Insert RAID extent 1. */
+	for (int i = 0; i < RST_TEST_NUM_DEVICES; i++) {
+		struct btrfs_io_stripe *stripe = &bioc->stripes[i];
+
+		stripe->dev = btrfs_device_by_devid(fs_info->fs_devices, i);
+		if (!stripe->dev) {
+			test_err("cannot find device with devid %d", i);
+			ret = -EINVAL;
+			goto out;
+		}
+
+		stripe->physical = logical1 + i * SZ_1G;
+	}
+
+	ret = btrfs_insert_one_raid_extent(trans, bioc);
+	if (ret) {
+		test_err("inserting RAID extent failed: %d", ret);
+		goto out;
+	}
+
+	bioc->logical = logical2;
+	/* Insert RAID extent 2, directly adjacent to it. */
+	for (int i = 0; i < RST_TEST_NUM_DEVICES; i++) {
+		struct btrfs_io_stripe *stripe = &bioc->stripes[i];
+
+		stripe->dev = btrfs_device_by_devid(fs_info->fs_devices, i);
+		if (!stripe->dev) {
+			test_err("cannot find device with devid %d", i);
+			ret = -EINVAL;
+			goto out;
+		}
+
+		stripe->physical = logical2 + i * SZ_1G;
+	}
+
+	ret = btrfs_insert_one_raid_extent(trans, bioc);
+	if (ret) {
+		test_err("inserting RAID extent failed: %d", ret);
+		goto out;
+	}
+
+	ret = btrfs_delete_raid_extent(trans, logical1 + SZ_512K, SZ_1M);
+	if (ret) {
+		test_err("deleting RAID extent [%llu, %llu] failed",
+			 logical1 + SZ_512K, (u64)SZ_1M);
+		goto out;
+	}
+
+	/* Verify item 1 is truncated to 512K. */
+	ret = btrfs_get_raid_extent_offset(fs_info, logical1, &len, map_type, 0,
+					   &io_stripe);
+	if (ret) {
+		test_err("lookup of RAID extent [%llu, %llu] failed", logical1,
+			 logical1 + len);
+		goto out;
+	}
+
+	if (io_stripe.physical != logical1) {
+		test_err("invalid physical address, expected %llu got %llu",
+			 logical1, io_stripe.physical);
+		ret = -EINVAL;
+		goto out;
+	}
+
+	if (len != SZ_512K) {
+		test_err("invalid stripe length, expected %llu got %llu",
+			 (u64)SZ_512K, len);
+		ret = -EINVAL;
+		goto out;
+	}
+
+	/* Verify item 2's start is moved by 512K. */
+	ret = btrfs_get_raid_extent_offset(fs_info, logical2 + SZ_512K, &len,
+					   map_type, 0, &io_stripe);
+	if (ret) {
+		test_err("lookup of RAID extent [%llu, %llu] failed",
+			 logical2 + SZ_512K, logical2 + len);
+		goto out;
+	}
+
+	if (io_stripe.physical != logical2 + SZ_512K) {
+		test_err("invalid physical address, expected %llu got %llu",
+			 logical2 + SZ_512K, io_stripe.physical);
+		ret = -EINVAL;
+		goto out;
+	}
+
+	if (len != SZ_512K) {
+		test_err("invalid stripe length, expected %llu got %llu",
+			 (u64)SZ_512K, len);
+		ret = -EINVAL;
+		goto out;
+	}
+
+	/* Verify there's a hole at [1M+512K, 2M+512K] . */
+	len = SZ_1M;
+	ret = btrfs_get_raid_extent_offset(fs_info, logical1 + SZ_512K, &len,
+					   map_type, 0, &io_stripe);
+	if (ret != -ENODATA) {
+		test_err("lookup of RAID [%llu, %llu] succeeded, should fail",
+			 logical1 + SZ_512K, logical1 + SZ_512K + len);
+		goto out;
+	}
+
+	/* Clean up after us. */
+	ret = btrfs_delete_raid_extent(trans, logical1, SZ_512K);
+	if (ret)
+		goto out;
+
+	ret = btrfs_delete_raid_extent(trans, logical2 + SZ_512K, SZ_512K);
+
+out:
+	btrfs_put_bioc(bioc);
+	return ret;
+}
+
+/*
  * Test a 64K RST write on a 2 disk RAID1 at a logical address of 1M and then
  * delete the 1st 32K, making the new start address 1M+32K.
  */
@@ -94,45 +703,45 @@ static int test_front_delete(struct btrfs_trans_handle *trans)
 		goto out;
 	}
 
-	ret = btrfs_delete_raid_extent(trans, logical, SZ_32K);
+	ret = btrfs_delete_raid_extent(trans, logical, SZ_16K);
 	if (ret) {
 		test_err("deleting RAID extent [%llu, %llu] failed", logical,
-			 logical + SZ_32K);
+			 logical + SZ_16K);
 		goto out;
 	}
 
-	len = SZ_32K;
-	ret = btrfs_get_raid_extent_offset(fs_info, logical + SZ_32K, &len,
+	len -= SZ_16K;
+	ret = btrfs_get_raid_extent_offset(fs_info, logical + SZ_16K, &len,
 					   map_type, 0, &io_stripe);
 	if (ret) {
 		test_err("lookup of RAID extent [%llu, %llu] failed",
-			 logical + SZ_32K, logical + SZ_32K + len);
+			 logical + SZ_16K, logical + SZ_64K);
 		goto out;
 	}
 
-	if (io_stripe.physical != logical + SZ_32K) {
+	if (io_stripe.physical != logical + SZ_16K) {
 		test_err("invalid physical address, expected %llu, got %llu",
-			 logical + SZ_32K, io_stripe.physical);
+			 logical + SZ_16K, io_stripe.physical);
 		ret = -EINVAL;
 		goto out;
 	}
 
-	if (len != SZ_32K) {
+	if (len != SZ_48K) {
 		test_err("invalid stripe length, expected %llu, got %llu",
-			 (u64)SZ_32K, len);
+			 (u64)SZ_48K, len);
 		ret = -EINVAL;
 		goto out;
 	}
 
 	ret = btrfs_get_raid_extent_offset(fs_info, logical, &len, map_type, 0, &io_stripe);
-	if (!ret) {
+	if (ret != -ENODATA) {
 		ret = -EINVAL;
 		test_err("lookup of RAID extent [%llu, %llu] succeeded, should fail",
-			 logical, logical + SZ_32K);
+			 logical, logical + SZ_16K);
 		goto out;
 	}
 
-	ret = btrfs_delete_raid_extent(trans, logical + SZ_32K, SZ_32K);
+	ret = btrfs_delete_raid_extent(trans, logical + SZ_16K, SZ_48K);
 out:
 	btrfs_put_bioc(bioc);
 	return ret;
@@ -209,14 +818,14 @@ static int test_tail_delete(struct btrfs_trans_handle *trans)
 		goto out;
 	}
 
-	ret = btrfs_delete_raid_extent(trans, logical + SZ_32K, SZ_32K);
+	ret = btrfs_delete_raid_extent(trans, logical + SZ_48K, SZ_16K);
 	if (ret) {
 		test_err("deleting RAID extent [%llu, %llu] failed",
-			 logical + SZ_32K, logical + SZ_64K);
+			 logical + SZ_48K, logical + SZ_64K);
 		goto out;
 	}
 
-	len = SZ_32K;
+	len = SZ_48K;
 	ret = btrfs_get_raid_extent_offset(fs_info, logical, &len, map_type, 0, &io_stripe);
 	if (ret) {
 		test_err("lookup of RAID extent [%llu, %llu] failed", logical,
@@ -231,9 +840,19 @@ static int test_tail_delete(struct btrfs_trans_handle *trans)
 		goto out;
 	}
 
-	if (len != SZ_32K) {
+	if (len != SZ_48K) {
 		test_err("invalid stripe length, expected %llu, got %llu",
-			 (u64)SZ_32K, len);
+			 (u64)SZ_48K, len);
+		ret = -EINVAL;
+		goto out;
+	}
+
+	len = SZ_16K;
+	ret = btrfs_get_raid_extent_offset(fs_info, logical + SZ_48K, &len,
+					   map_type, 0, &io_stripe);
+	if (ret != -ENODATA) {
+		test_err("lookup of RAID extent [%llu, %llu] succeeded should fail",
+			 logical + SZ_48K, logical + SZ_64K);
 		ret = -EINVAL;
 		goto out;
 	}
@@ -456,6 +1075,10 @@ static const test_func_t tests[] = {
 	test_create_update_delete,
 	test_tail_delete,
 	test_front_delete,
+	test_front_delete_prev_item,
+	test_punch_hole,
+	test_punch_hole_3extents,
+	test_delete_two_extents,
 };
 
 static int run_test(test_func_t test, u32 sectorsize, u32 nodesize)
@@ -478,8 +1101,8 @@ static int run_test(test_func_t test, u32 sectorsize, u32 nodesize)
 		ret = PTR_ERR(root);
 		goto out;
 	}
-	btrfs_set_super_compat_ro_flags(root->fs_info->super_copy,
-					BTRFS_FEATURE_INCOMPAT_RAID_STRIPE_TREE);
+	btrfs_set_super_incompat_flags(root->fs_info->super_copy,
+				       BTRFS_FEATURE_INCOMPAT_RAID_STRIPE_TREE);
 	root->root_key.objectid = BTRFS_RAID_STRIPE_TREE_OBJECTID;
 	root->root_key.type = BTRFS_ROOT_ITEM_KEY;
 	root->root_key.offset = 0;
diff --git a/fs/btrfs/transaction.c b/fs/btrfs/transaction.c
index dc0b837..aca83a9 100644
--- a/fs/btrfs/transaction.c
+++ b/fs/btrfs/transaction.c
@@ -274,8 +274,10 @@ static noinline int join_transaction(struct btrfs_fs_info *fs_info,
 	cur_trans = fs_info->running_transaction;
 	if (cur_trans) {
 		if (TRANS_ABORTED(cur_trans)) {
+			const int abort_error = cur_trans->aborted;
+
 			spin_unlock(&fs_info->trans_lock);
-			return cur_trans->aborted;
+			return abort_error;
 		}
 		if (btrfs_blocked_trans_types[cur_trans->state] & type) {
 			spin_unlock(&fs_info->trans_lock);
@@ -795,8 +797,7 @@ start_transaction(struct btrfs_root *root, unsigned int num_items,
 	if (num_bytes)
 		btrfs_block_rsv_release(fs_info, trans_rsv, num_bytes, NULL);
 	if (delayed_refs_bytes)
-		btrfs_space_info_free_bytes_may_use(fs_info, trans_rsv->space_info,
-						    delayed_refs_bytes);
+		btrfs_space_info_free_bytes_may_use(trans_rsv->space_info, delayed_refs_bytes);
 reserve_fail:
 	btrfs_qgroup_free_meta_prealloc(root, qgroup_reserved);
 	return ERR_PTR(ret);
diff --git a/fs/btrfs/transaction.h b/fs/btrfs/transaction.h
index 184fa5c..9f7c777 100644
--- a/fs/btrfs/transaction.h
+++ b/fs/btrfs/transaction.h
@@ -227,7 +227,21 @@ static inline void btrfs_clear_skip_qgroup(struct btrfs_trans_handle *trans)
 	delayed_refs->qgroup_to_skip = 0;
 }
 
-bool __cold abort_should_print_stack(int error);
+/*
+ * We want the transaction abort to print stack trace only for errors where the
+ * cause could be a bug, eg. due to ENOSPC, and not for common errors that are
+ * caused by external factors.
+ */
+static inline bool btrfs_abort_should_print_stack(int error)
+{
+	switch (error) {
+	case -EIO:
+	case -EROFS:
+	case -ENOMEM:
+		return false;
+	}
+	return true;
+}
 
 /*
  * Call btrfs_abort_transaction as early as possible when an error condition is
@@ -240,7 +254,7 @@ do {								\
 	if (!test_and_set_bit(BTRFS_FS_STATE_TRANS_ABORTED,	\
 			&((trans)->fs_info->fs_state))) {	\
 		__first = true;					\
-		if (WARN(abort_should_print_stack(error),	\
+		if (WARN(btrfs_abort_should_print_stack(error),	\
 			KERN_ERR				\
 			"BTRFS: Transaction aborted (error %d)\n",	\
 			(error))) {					\
diff --git a/fs/btrfs/tree-checker.c b/fs/btrfs/tree-checker.c
index dfeee033..43979891 100644
--- a/fs/btrfs/tree-checker.c
+++ b/fs/btrfs/tree-checker.c
@@ -764,22 +764,19 @@ static int check_block_group_item(struct extent_buffer *leaf,
 	return 0;
 }
 
-__printf(4, 5)
+__printf(5, 6)
 __cold
-static void chunk_err(const struct extent_buffer *leaf,
+static void chunk_err(const struct btrfs_fs_info *fs_info,
+		      const struct extent_buffer *leaf,
 		      const struct btrfs_chunk *chunk, u64 logical,
 		      const char *fmt, ...)
 {
-	const struct btrfs_fs_info *fs_info = leaf->fs_info;
-	bool is_sb;
+	bool is_sb = !leaf;
 	struct va_format vaf;
 	va_list args;
 	int i;
 	int slot = -1;
 
-	/* Only superblock eb is able to have such small offset */
-	is_sb = (leaf->start == BTRFS_SUPER_INFO_OFFSET);
-
 	if (!is_sb) {
 		/*
 		 * Get the slot number by iterating through all slots, this
@@ -812,13 +809,17 @@ static void chunk_err(const struct extent_buffer *leaf,
 /*
  * The common chunk check which could also work on super block sys chunk array.
  *
+ * If @leaf is NULL, then @chunk must be an on-stack chunk item.
+ * (For superblock sys_chunk array, and fs_info->sectorsize is unreliable)
+ *
  * Return -EUCLEAN if anything is corrupted.
  * Return 0 if everything is OK.
  */
-int btrfs_check_chunk_valid(struct extent_buffer *leaf,
-			    struct btrfs_chunk *chunk, u64 logical)
+int btrfs_check_chunk_valid(const struct btrfs_fs_info *fs_info,
+			    const struct extent_buffer *leaf,
+			    const struct btrfs_chunk *chunk, u64 logical,
+			    u32 sectorsize)
 {
-	struct btrfs_fs_info *fs_info = leaf->fs_info;
 	u64 length;
 	u64 chunk_end;
 	u64 stripe_len;
@@ -826,63 +827,73 @@ int btrfs_check_chunk_valid(struct extent_buffer *leaf,
 	u16 sub_stripes;
 	u64 type;
 	u64 features;
+	u32 chunk_sector_size;
 	bool mixed = false;
 	int raid_index;
 	int nparity;
 	int ncopies;
 
-	length = btrfs_chunk_length(leaf, chunk);
-	stripe_len = btrfs_chunk_stripe_len(leaf, chunk);
-	num_stripes = btrfs_chunk_num_stripes(leaf, chunk);
-	sub_stripes = btrfs_chunk_sub_stripes(leaf, chunk);
-	type = btrfs_chunk_type(leaf, chunk);
+	if (leaf) {
+		length = btrfs_chunk_length(leaf, chunk);
+		stripe_len = btrfs_chunk_stripe_len(leaf, chunk);
+		num_stripes = btrfs_chunk_num_stripes(leaf, chunk);
+		sub_stripes = btrfs_chunk_sub_stripes(leaf, chunk);
+		type = btrfs_chunk_type(leaf, chunk);
+		chunk_sector_size = btrfs_chunk_sector_size(leaf, chunk);
+	} else {
+		length = btrfs_stack_chunk_length(chunk);
+		stripe_len = btrfs_stack_chunk_stripe_len(chunk);
+		num_stripes = btrfs_stack_chunk_num_stripes(chunk);
+		sub_stripes = btrfs_stack_chunk_sub_stripes(chunk);
+		type = btrfs_stack_chunk_type(chunk);
+		chunk_sector_size = btrfs_stack_chunk_sector_size(chunk);
+	}
 	raid_index = btrfs_bg_flags_to_raid_index(type);
 	ncopies = btrfs_raid_array[raid_index].ncopies;
 	nparity = btrfs_raid_array[raid_index].nparity;
 
 	if (unlikely(!num_stripes)) {
-		chunk_err(leaf, chunk, logical,
+		chunk_err(fs_info, leaf, chunk, logical,
 			  "invalid chunk num_stripes, have %u", num_stripes);
 		return -EUCLEAN;
 	}
 	if (unlikely(num_stripes < ncopies)) {
-		chunk_err(leaf, chunk, logical,
+		chunk_err(fs_info, leaf, chunk, logical,
 			  "invalid chunk num_stripes < ncopies, have %u < %d",
 			  num_stripes, ncopies);
 		return -EUCLEAN;
 	}
 	if (unlikely(nparity && num_stripes == nparity)) {
-		chunk_err(leaf, chunk, logical,
+		chunk_err(fs_info, leaf, chunk, logical,
 			  "invalid chunk num_stripes == nparity, have %u == %d",
 			  num_stripes, nparity);
 		return -EUCLEAN;
 	}
-	if (unlikely(!IS_ALIGNED(logical, fs_info->sectorsize))) {
-		chunk_err(leaf, chunk, logical,
+	if (unlikely(!IS_ALIGNED(logical, sectorsize))) {
+		chunk_err(fs_info, leaf, chunk, logical,
 		"invalid chunk logical, have %llu should aligned to %u",
-			  logical, fs_info->sectorsize);
+			  logical, sectorsize);
 		return -EUCLEAN;
 	}
-	if (unlikely(btrfs_chunk_sector_size(leaf, chunk) != fs_info->sectorsize)) {
-		chunk_err(leaf, chunk, logical,
+	if (unlikely(chunk_sector_size != sectorsize)) {
+		chunk_err(fs_info, leaf, chunk, logical,
 			  "invalid chunk sectorsize, have %u expect %u",
-			  btrfs_chunk_sector_size(leaf, chunk),
-			  fs_info->sectorsize);
+			  chunk_sector_size, sectorsize);
 		return -EUCLEAN;
 	}
-	if (unlikely(!length || !IS_ALIGNED(length, fs_info->sectorsize))) {
-		chunk_err(leaf, chunk, logical,
+	if (unlikely(!length || !IS_ALIGNED(length, sectorsize))) {
+		chunk_err(fs_info, leaf, chunk, logical,
 			  "invalid chunk length, have %llu", length);
 		return -EUCLEAN;
 	}
 	if (unlikely(check_add_overflow(logical, length, &chunk_end))) {
-		chunk_err(leaf, chunk, logical,
+		chunk_err(fs_info, leaf, chunk, logical,
 "invalid chunk logical start and length, have logical start %llu length %llu",
 			  logical, length);
 		return -EUCLEAN;
 	}
 	if (unlikely(!is_power_of_2(stripe_len) || stripe_len != BTRFS_STRIPE_LEN)) {
-		chunk_err(leaf, chunk, logical,
+		chunk_err(fs_info, leaf, chunk, logical,
 			  "invalid chunk stripe length: %llu",
 			  stripe_len);
 		return -EUCLEAN;
@@ -896,30 +907,29 @@ int btrfs_check_chunk_valid(struct extent_buffer *leaf,
 	 * Thus it should be a good way to catch obvious bitflips.
 	 */
 	if (unlikely(length >= btrfs_stripe_nr_to_offset(U32_MAX))) {
-		chunk_err(leaf, chunk, logical,
+		chunk_err(fs_info, leaf, chunk, logical,
 			  "chunk length too large: have %llu limit %llu",
 			  length, btrfs_stripe_nr_to_offset(U32_MAX));
 		return -EUCLEAN;
 	}
 	if (unlikely(type & ~(BTRFS_BLOCK_GROUP_TYPE_MASK |
 			      BTRFS_BLOCK_GROUP_PROFILE_MASK))) {
-		chunk_err(leaf, chunk, logical,
+		chunk_err(fs_info, leaf, chunk, logical,
 			  "unrecognized chunk type: 0x%llx",
 			  ~(BTRFS_BLOCK_GROUP_TYPE_MASK |
-			    BTRFS_BLOCK_GROUP_PROFILE_MASK) &
-			  btrfs_chunk_type(leaf, chunk));
+			    BTRFS_BLOCK_GROUP_PROFILE_MASK) & type);
 		return -EUCLEAN;
 	}
 
 	if (unlikely(!has_single_bit_set(type & BTRFS_BLOCK_GROUP_PROFILE_MASK) &&
 		     (type & BTRFS_BLOCK_GROUP_PROFILE_MASK) != 0)) {
-		chunk_err(leaf, chunk, logical,
+		chunk_err(fs_info, leaf, chunk, logical,
 		"invalid chunk profile flag: 0x%llx, expect 0 or 1 bit set",
 			  type & BTRFS_BLOCK_GROUP_PROFILE_MASK);
 		return -EUCLEAN;
 	}
 	if (unlikely((type & BTRFS_BLOCK_GROUP_TYPE_MASK) == 0)) {
-		chunk_err(leaf, chunk, logical,
+		chunk_err(fs_info, leaf, chunk, logical,
 	"missing chunk type flag, have 0x%llx one bit must be set in 0x%llx",
 			  type, BTRFS_BLOCK_GROUP_TYPE_MASK);
 		return -EUCLEAN;
@@ -928,7 +938,7 @@ int btrfs_check_chunk_valid(struct extent_buffer *leaf,
 	if (unlikely((type & BTRFS_BLOCK_GROUP_SYSTEM) &&
 		     (type & (BTRFS_BLOCK_GROUP_METADATA |
 			      BTRFS_BLOCK_GROUP_DATA)))) {
-		chunk_err(leaf, chunk, logical,
+		chunk_err(fs_info, leaf, chunk, logical,
 			  "system chunk with data or metadata type: 0x%llx",
 			  type);
 		return -EUCLEAN;
@@ -941,7 +951,7 @@ int btrfs_check_chunk_valid(struct extent_buffer *leaf,
 	if (!mixed) {
 		if (unlikely((type & BTRFS_BLOCK_GROUP_METADATA) &&
 			     (type & BTRFS_BLOCK_GROUP_DATA))) {
-			chunk_err(leaf, chunk, logical,
+			chunk_err(fs_info, leaf, chunk, logical,
 			"mixed chunk type in non-mixed mode: 0x%llx", type);
 			return -EUCLEAN;
 		}
@@ -963,7 +973,7 @@ int btrfs_check_chunk_valid(struct extent_buffer *leaf,
 		      num_stripes != btrfs_raid_array[BTRFS_RAID_DUP].dev_stripes) ||
 		     ((type & BTRFS_BLOCK_GROUP_PROFILE_MASK) == 0 &&
 		      num_stripes != btrfs_raid_array[BTRFS_RAID_SINGLE].dev_stripes))) {
-		chunk_err(leaf, chunk, logical,
+		chunk_err(fs_info, leaf, chunk, logical,
 			"invalid num_stripes:sub_stripes %u:%u for profile %llu",
 			num_stripes, sub_stripes,
 			type & BTRFS_BLOCK_GROUP_PROFILE_MASK);
@@ -983,14 +993,15 @@ static int check_leaf_chunk_item(struct extent_buffer *leaf,
 				 struct btrfs_chunk *chunk,
 				 struct btrfs_key *key, int slot)
 {
+	struct btrfs_fs_info *fs_info = leaf->fs_info;
 	int num_stripes;
 
 	if (unlikely(btrfs_item_size(leaf, slot) < sizeof(struct btrfs_chunk))) {
-		chunk_err(leaf, chunk, key->offset,
+		chunk_err(fs_info, leaf, chunk, key->offset,
 			"invalid chunk item size: have %u expect [%zu, %u)",
 			btrfs_item_size(leaf, slot),
 			sizeof(struct btrfs_chunk),
-			BTRFS_LEAF_DATA_SIZE(leaf->fs_info));
+			BTRFS_LEAF_DATA_SIZE(fs_info));
 		return -EUCLEAN;
 	}
 
@@ -1001,14 +1012,15 @@ static int check_leaf_chunk_item(struct extent_buffer *leaf,
 
 	if (unlikely(btrfs_chunk_item_size(num_stripes) !=
 		     btrfs_item_size(leaf, slot))) {
-		chunk_err(leaf, chunk, key->offset,
+		chunk_err(fs_info, leaf, chunk, key->offset,
 			"invalid chunk item size: have %u expect %lu",
 			btrfs_item_size(leaf, slot),
 			btrfs_chunk_item_size(num_stripes));
 		return -EUCLEAN;
 	}
 out:
-	return btrfs_check_chunk_valid(leaf, chunk, key->offset);
+	return btrfs_check_chunk_valid(fs_info, leaf, chunk, key->offset,
+				       fs_info->sectorsize);
 }
 
 __printf(3, 4)
diff --git a/fs/btrfs/tree-checker.h b/fs/btrfs/tree-checker.h
index db67f96..eb201f4 100644
--- a/fs/btrfs/tree-checker.h
+++ b/fs/btrfs/tree-checker.h
@@ -10,6 +10,7 @@
 #include <uapi/linux/btrfs_tree.h>
 
 struct extent_buffer;
+struct btrfs_fs_info;
 struct btrfs_chunk;
 struct btrfs_key;
 
@@ -66,8 +67,10 @@ enum btrfs_tree_block_status __btrfs_check_node(struct extent_buffer *node);
 int btrfs_check_leaf(struct extent_buffer *leaf);
 int btrfs_check_node(struct extent_buffer *node);
 
-int btrfs_check_chunk_valid(struct extent_buffer *leaf,
-			    struct btrfs_chunk *chunk, u64 logical);
+int btrfs_check_chunk_valid(const struct btrfs_fs_info *fs_info,
+			    const struct extent_buffer *leaf,
+			    const struct btrfs_chunk *chunk, u64 logical,
+			    u32 sectorsize);
 int btrfs_check_eb_owner(const struct extent_buffer *eb, u64 root_owner);
 int btrfs_verify_level_key(struct extent_buffer *eb,
 			   const struct btrfs_tree_parent_check *check);
diff --git a/fs/btrfs/tree-log.c b/fs/btrfs/tree-log.c
index c8d6587..955d167 100644
--- a/fs/btrfs/tree-log.c
+++ b/fs/btrfs/tree-log.c
@@ -590,7 +590,6 @@ static int overwrite_item(struct btrfs_trans_handle *trans,
 		}
 	}
 no_copy:
-	btrfs_mark_buffer_dirty(trans, path->nodes[0]);
 	btrfs_release_path(path);
 	return 0;
 }
@@ -3588,7 +3587,6 @@ static noinline int insert_dir_log_key(struct btrfs_trans_handle *trans,
 		last_offset = max(last_offset, curr_end);
 	}
 	btrfs_set_dir_log_end(path->nodes[0], item, last_offset);
-	btrfs_mark_buffer_dirty(trans, path->nodes[0]);
 	btrfs_release_path(path);
 	return 0;
 }
@@ -4566,7 +4564,6 @@ static noinline int copy_items(struct btrfs_trans_handle *trans,
 		dst_index++;
 	}
 
-	btrfs_mark_buffer_dirty(trans, dst_path->nodes[0]);
 	btrfs_release_path(dst_path);
 out:
 	kfree(ins_data);
@@ -4776,7 +4773,6 @@ static int log_one_extent(struct btrfs_trans_handle *trans,
 	write_extent_buffer(leaf, &fi,
 			    btrfs_item_ptr_offset(leaf, path->slots[0]),
 			    sizeof(fi));
-	btrfs_mark_buffer_dirty(trans, leaf);
 
 	btrfs_release_path(path);
 
diff --git a/fs/btrfs/uuid-tree.c b/fs/btrfs/uuid-tree.c
index aca2861..17b5e81 100644
--- a/fs/btrfs/uuid-tree.c
+++ b/fs/btrfs/uuid-tree.c
@@ -140,8 +140,6 @@ int btrfs_uuid_tree_add(struct btrfs_trans_handle *trans, const u8 *uuid, u8 typ
 	ret = 0;
 	subid_le = cpu_to_le64(subid_cpu);
 	write_extent_buffer(eb, &subid_le, offset, sizeof(subid_le));
-	btrfs_mark_buffer_dirty(trans, eb);
-
 out:
 	btrfs_free_path(path);
 	return ret;
diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c
index 1cccaf9..a594f66 100644
--- a/fs/btrfs/volumes.c
+++ b/fs/btrfs/volumes.c
@@ -13,8 +13,8 @@
 #include <linux/list_sort.h>
 #include <linux/namei.h>
 #include "misc.h"
-#include "ctree.h"
 #include "disk-io.h"
+#include "extent-tree.h"
 #include "transaction.h"
 #include "volumes.h"
 #include "raid56.h"
@@ -48,6 +48,7 @@ struct btrfs_io_geometry {
 	u64 raid56_full_stripe_start;
 	int max_errors;
 	enum btrfs_map_op op;
+	bool use_rst;
 };
 
 const struct btrfs_raid_attr btrfs_raid_array[BTRFS_NR_RAID_TYPES] = {
@@ -1298,6 +1299,7 @@ static int open_fs_devices(struct btrfs_fs_devices *fs_devices,
 	struct btrfs_device *device;
 	struct btrfs_device *latest_dev = NULL;
 	struct btrfs_device *tmp_device;
+	s64 __maybe_unused value = 0;
 	int ret = 0;
 
 	list_for_each_entry_safe(device, tmp_device, &fs_devices->devices,
@@ -1327,7 +1329,23 @@ static int open_fs_devices(struct btrfs_fs_devices *fs_devices,
 	fs_devices->latest_dev = latest_dev;
 	fs_devices->total_rw_bytes = 0;
 	fs_devices->chunk_alloc_policy = BTRFS_CHUNK_ALLOC_REGULAR;
+#ifdef CONFIG_BTRFS_EXPERIMENTAL
+	fs_devices->rr_min_contig_read = BTRFS_DEFAULT_RR_MIN_CONTIG_READ;
+	fs_devices->read_devid = latest_dev->devid;
+	fs_devices->read_policy = btrfs_read_policy_to_enum(btrfs_get_mod_read_policy(),
+							    &value);
+	if (fs_devices->read_policy == BTRFS_READ_POLICY_RR)
+		fs_devices->collect_fs_stats = true;
+
+	if (value) {
+		if (fs_devices->read_policy == BTRFS_READ_POLICY_RR)
+			fs_devices->rr_min_contig_read = value;
+		if (fs_devices->read_policy == BTRFS_READ_POLICY_DEVID)
+			fs_devices->read_devid = value;
+	}
+#else
 	fs_devices->read_policy = BTRFS_READ_POLICY_PID;
+#endif
 
 	return 0;
 }
@@ -2045,7 +2063,6 @@ static int btrfs_add_dev_item(struct btrfs_trans_handle *trans,
 	ptr = btrfs_device_fsid(dev_item);
 	write_extent_buffer(leaf, trans->fs_info->fs_devices->metadata_uuid,
 			    ptr, BTRFS_FSID_SIZE);
-	btrfs_mark_buffer_dirty(trans, leaf);
 
 	ret = 0;
 out:
@@ -2741,11 +2758,9 @@ static int btrfs_finish_sprout(struct btrfs_trans_handle *trans)
 		device = btrfs_find_device(fs_info->fs_devices, &args);
 		BUG_ON(!device); /* Logic error */
 
-		if (device->fs_devices->seeding) {
+		if (device->fs_devices->seeding)
 			btrfs_set_device_generation(leaf, dev_item,
 						    device->generation);
-			btrfs_mark_buffer_dirty(trans, leaf);
-		}
 
 		path->slots[0]++;
 		goto next_slot;
@@ -3038,8 +3053,6 @@ static noinline int btrfs_update_device(struct btrfs_trans_handle *trans,
 				     btrfs_device_get_disk_total_bytes(device));
 	btrfs_set_device_bytes_used(leaf, dev_item,
 				    btrfs_device_get_bytes_used(device));
-	btrfs_mark_buffer_dirty(trans, leaf);
-
 out:
 	btrfs_free_path(path);
 	return ret;
@@ -3748,10 +3761,7 @@ static int insert_balance_item(struct btrfs_fs_info *fs_info,
 	btrfs_set_balance_meta(leaf, item, &disk_bargs);
 	btrfs_cpu_balance_args_to_disk(&disk_bargs, &bctl->sys);
 	btrfs_set_balance_sys(leaf, item, &disk_bargs);
-
 	btrfs_set_balance_flags(leaf, item, bctl->flags);
-
-	btrfs_mark_buffer_dirty(trans, leaf);
 out:
 	btrfs_free_path(path);
 	err = btrfs_commit_transaction(trans);
@@ -5513,33 +5523,34 @@ void btrfs_remove_chunk_map(struct btrfs_fs_info *fs_info, struct btrfs_chunk_ma
 	btrfs_free_chunk_map(map);
 }
 
+static int btrfs_chunk_map_cmp(const struct rb_node *new,
+			       const struct rb_node *exist)
+{
+	const struct btrfs_chunk_map *new_map =
+		rb_entry(new, struct btrfs_chunk_map, rb_node);
+	const struct btrfs_chunk_map *exist_map =
+		rb_entry(exist, struct btrfs_chunk_map, rb_node);
+
+	if (new_map->start == exist_map->start)
+		return 0;
+	if (new_map->start < exist_map->start)
+		return -1;
+	return 1;
+}
+
 EXPORT_FOR_TESTS
 int btrfs_add_chunk_map(struct btrfs_fs_info *fs_info, struct btrfs_chunk_map *map)
 {
-	struct rb_node **p;
-	struct rb_node *parent = NULL;
-	bool leftmost = true;
+	struct rb_node *exist;
 
 	write_lock(&fs_info->mapping_tree_lock);
-	p = &fs_info->mapping_tree.rb_root.rb_node;
-	while (*p) {
-		struct btrfs_chunk_map *entry;
+	exist = rb_find_add_cached(&map->rb_node, &fs_info->mapping_tree,
+				   btrfs_chunk_map_cmp);
 
-		parent = *p;
-		entry = rb_entry(parent, struct btrfs_chunk_map, rb_node);
-
-		if (map->start < entry->start) {
-			p = &(*p)->rb_left;
-		} else if (map->start > entry->start) {
-			p = &(*p)->rb_right;
-			leftmost = false;
-		} else {
-			write_unlock(&fs_info->mapping_tree_lock);
-			return -EEXIST;
-		}
+	if (exist) {
+		write_unlock(&fs_info->mapping_tree_lock);
+		return -EEXIST;
 	}
-	rb_link_node(&map->rb_node, parent, p);
-	rb_insert_color_cached(&map->rb_node, &fs_info->mapping_tree, leftmost);
 	chunk_map_device_set_bits(map, CHUNK_ALLOCATED);
 	chunk_map_device_clear_bits(map, CHUNK_TRIMMED);
 	write_unlock(&fs_info->mapping_tree_lock);
@@ -5959,6 +5970,76 @@ unsigned long btrfs_full_stripe_len(struct btrfs_fs_info *fs_info,
 	return len;
 }
 
+#ifdef CONFIG_BTRFS_EXPERIMENTAL
+static int btrfs_read_preferred(struct btrfs_chunk_map *map, int first, int num_stripes)
+{
+	for (int index = first; index < first + num_stripes; index++) {
+		const struct btrfs_device *device = map->stripes[index].dev;
+
+		if (device->devid == READ_ONCE(device->fs_devices->read_devid))
+			return index;
+	}
+
+	/* If no read-preferred device is set use the first stripe. */
+	return first;
+}
+
+struct stripe_mirror {
+	u64 devid;
+	int num;
+};
+
+static int btrfs_cmp_devid(const void *a, const void *b)
+{
+	const struct stripe_mirror *s1 = (const struct stripe_mirror *)a;
+	const struct stripe_mirror *s2 = (const struct stripe_mirror *)b;
+
+	if (s1->devid < s2->devid)
+		return -1;
+	if (s1->devid > s2->devid)
+		return 1;
+	return 0;
+}
+
+/*
+ * Select a stripe for reading using the round-robin algorithm.
+ *
+ *  1. Compute the read cycle as the total sectors read divided by the minimum
+ *     sectors per device.
+ *  2. Determine the stripe number for the current read by taking the modulus
+ *     of the read cycle with the total number of stripes:
+ *
+ *      stripe index = (total sectors / min sectors per dev) % num stripes
+ *
+ * The calculated stripe index is then used to select the corresponding device
+ * from the list of devices, which is ordered by devid.
+ */
+static int btrfs_read_rr(const struct btrfs_chunk_map *map, int first, int num_stripes)
+{
+	struct stripe_mirror stripes[BTRFS_RAID1_MAX_MIRRORS] = { 0 };
+	struct btrfs_device *device  = map->stripes[first].dev;
+	struct btrfs_fs_info *fs_info = device->fs_devices->fs_info;
+	unsigned int read_cycle;
+	unsigned int total_reads;
+	unsigned int min_reads_per_dev;
+
+	total_reads = percpu_counter_sum(&fs_info->stats_read_blocks);
+	min_reads_per_dev = READ_ONCE(fs_info->fs_devices->rr_min_contig_read) >>
+						       fs_info->sectorsize_bits;
+
+	for (int index = 0, i = first; i < first + num_stripes; i++) {
+		stripes[index].devid = map->stripes[i].dev->devid;
+		stripes[index].num = i;
+		index++;
+	}
+	sort(stripes, num_stripes, sizeof(struct stripe_mirror),
+	     btrfs_cmp_devid, NULL);
+
+	read_cycle = total_reads / min_reads_per_dev;
+	return stripes[read_cycle % num_stripes].num;
+}
+#endif
+
 static int find_live_mirror(struct btrfs_fs_info *fs_info,
 			    struct btrfs_chunk_map *map, int first,
 			    int dev_replace_is_ongoing)
@@ -5988,6 +6069,14 @@ static int find_live_mirror(struct btrfs_fs_info *fs_info,
 	case BTRFS_READ_POLICY_PID:
 		preferred_mirror = first + (current->pid % num_stripes);
 		break;
+#ifdef CONFIG_BTRFS_EXPERIMENTAL
+	case BTRFS_READ_POLICY_RR:
+		preferred_mirror = btrfs_read_rr(map, first, num_stripes);
+		break;
+	case BTRFS_READ_POLICY_DEVID:
+		preferred_mirror = btrfs_read_preferred(map, first, num_stripes);
+		break;
+#endif
 	}
 
 	if (dev_replace_is_ongoing &&
@@ -6346,8 +6435,7 @@ static int set_io_stripe(struct btrfs_fs_info *fs_info, u64 logical,
 {
 	dst->dev = map->stripes[io_geom->stripe_index].dev;
 
-	if (io_geom->op == BTRFS_MAP_READ &&
-	    btrfs_need_stripe_tree_update(fs_info, map->type))
+	if (io_geom->op == BTRFS_MAP_READ && io_geom->use_rst)
 		return btrfs_get_raid_extent_offset(fs_info, logical, length,
 						    map->type,
 						    io_geom->stripe_index, dst);
@@ -6362,7 +6450,7 @@ static bool is_single_device_io(struct btrfs_fs_info *fs_info,
 				const struct btrfs_io_stripe *smap,
 				const struct btrfs_chunk_map *map,
 				int num_alloc_stripes,
-				enum btrfs_map_op op, int mirror_num)
+				struct btrfs_io_geometry *io_geom)
 {
 	if (!smap)
 		return false;
@@ -6370,10 +6458,10 @@ static bool is_single_device_io(struct btrfs_fs_info *fs_info,
 	if (num_alloc_stripes != 1)
 		return false;
 
-	if (btrfs_need_stripe_tree_update(fs_info, map->type) && op != BTRFS_MAP_READ)
+	if (io_geom->use_rst && io_geom->op != BTRFS_MAP_READ)
 		return false;
 
-	if ((map->type & BTRFS_BLOCK_GROUP_RAID56_MASK) && mirror_num > 1)
+	if ((map->type & BTRFS_BLOCK_GROUP_RAID56_MASK) && io_geom->mirror_num > 1)
 		return false;
 
 	return true;
@@ -6579,6 +6667,7 @@ int btrfs_map_block(struct btrfs_fs_info *fs_info, enum btrfs_map_op op,
 	io_geom.raid56_full_stripe_start = (u64)-1;
 	max_len = btrfs_max_io_len(map, map_offset, &io_geom);
 	*length = min_t(u64, map->chunk_len - map_offset, max_len);
+	io_geom.use_rst = btrfs_need_stripe_tree_update(fs_info, map->type);
 
 	if (dev_replace->replace_task != current)
 		down_read(&dev_replace->rwsem);
@@ -6647,8 +6736,7 @@ int btrfs_map_block(struct btrfs_fs_info *fs_info, enum btrfs_map_op op,
 	 * physical block information on the stack instead of allocating an
 	 * I/O context structure.
 	 */
-	if (is_single_device_io(fs_info, smap, map, num_alloc_stripes, op,
-				io_geom.mirror_num)) {
+	if (is_single_device_io(fs_info, smap, map, num_alloc_stripes, &io_geom)) {
 		ret = set_io_stripe(fs_info, logical, length, smap, map, &io_geom);
 		if (mirror_num_ret)
 			*mirror_num_ret = io_geom.mirror_num;
@@ -6662,6 +6750,7 @@ int btrfs_map_block(struct btrfs_fs_info *fs_info, enum btrfs_map_op op,
 		goto out;
 	}
 	bioc->map_type = map->type;
+	bioc->use_rst = io_geom.use_rst;
 
 	/*
 	 * For RAID56 full map, we need to make sure the stripes[] follows the
@@ -7002,16 +7091,6 @@ static int read_one_chunk(struct btrfs_key *key, struct extent_buffer *leaf,
 	warn_32bit_meta_chunk(fs_info, logical, length, type);
 #endif
 
-	/*
-	 * Only need to verify chunk item if we're reading from sys chunk array,
-	 * as chunk item in tree block is already verified by tree-checker.
-	 */
-	if (leaf->start == BTRFS_SUPER_INFO_OFFSET) {
-		ret = btrfs_check_chunk_valid(leaf, chunk, logical);
-		if (ret)
-			return ret;
-	}
-
 	map = btrfs_find_chunk_map(fs_info, logical, 1);
 
 	/* already mapped? */
@@ -7269,16 +7348,11 @@ int btrfs_read_sys_array(struct btrfs_fs_info *fs_info)
 {
 	struct btrfs_super_block *super_copy = fs_info->super_copy;
 	struct extent_buffer *sb;
-	struct btrfs_disk_key *disk_key;
-	struct btrfs_chunk *chunk;
 	u8 *array_ptr;
 	unsigned long sb_array_offset;
 	int ret = 0;
-	u32 num_stripes;
 	u32 array_size;
-	u32 len = 0;
 	u32 cur_offset;
-	u64 type;
 	struct btrfs_key key;
 
 	ASSERT(BTRFS_SUPER_INFO_SIZE <= fs_info->nodesize);
@@ -7301,10 +7375,15 @@ int btrfs_read_sys_array(struct btrfs_fs_info *fs_info)
 	cur_offset = 0;
 
 	while (cur_offset < array_size) {
-		disk_key = (struct btrfs_disk_key *)array_ptr;
-		len = sizeof(*disk_key);
-		if (cur_offset + len > array_size)
-			goto out_short_read;
+		struct btrfs_chunk *chunk;
+		struct btrfs_disk_key *disk_key = (struct btrfs_disk_key *)array_ptr;
+		u32 len = sizeof(*disk_key);
+
+		/*
+		 * The sys_chunk_array has been already verified at super block
+		 * read time.  Only do ASSERT()s for basic checks.
+		 */
+		ASSERT(cur_offset + len <= array_size);
 
 		btrfs_disk_key_to_cpu(&key, disk_key);
 
@@ -7312,44 +7391,14 @@ int btrfs_read_sys_array(struct btrfs_fs_info *fs_info)
 		sb_array_offset += len;
 		cur_offset += len;
 
-		if (key.type != BTRFS_CHUNK_ITEM_KEY) {
-			btrfs_err(fs_info,
-			    "unexpected item type %u in sys_array at offset %u",
-				  (u32)key.type, cur_offset);
-			ret = -EIO;
-			break;
-		}
+		ASSERT(key.type == BTRFS_CHUNK_ITEM_KEY);
 
 		chunk = (struct btrfs_chunk *)sb_array_offset;
-		/*
-		 * At least one btrfs_chunk with one stripe must be present,
-		 * exact stripe count check comes afterwards
-		 */
-		len = btrfs_chunk_item_size(1);
-		if (cur_offset + len > array_size)
-			goto out_short_read;
+		ASSERT(btrfs_chunk_type(sb, chunk) & BTRFS_BLOCK_GROUP_SYSTEM);
 
-		num_stripes = btrfs_chunk_num_stripes(sb, chunk);
-		if (!num_stripes) {
-			btrfs_err(fs_info,
-			"invalid number of stripes %u in sys_array at offset %u",
-				  num_stripes, cur_offset);
-			ret = -EIO;
-			break;
-		}
+		len = btrfs_chunk_item_size(btrfs_chunk_num_stripes(sb, chunk));
 
-		type = btrfs_chunk_type(sb, chunk);
-		if ((type & BTRFS_BLOCK_GROUP_SYSTEM) == 0) {
-			btrfs_err(fs_info,
-			"invalid chunk type %llu in sys_array at offset %u",
-				  type, cur_offset);
-			ret = -EIO;
-			break;
-		}
-
-		len = btrfs_chunk_item_size(num_stripes);
-		if (cur_offset + len > array_size)
-			goto out_short_read;
+		ASSERT(cur_offset + len <= array_size);
 
 		ret = read_one_chunk(&key, sb, chunk);
 		if (ret)
@@ -7362,13 +7411,6 @@ int btrfs_read_sys_array(struct btrfs_fs_info *fs_info)
 	clear_extent_buffer_uptodate(sb);
 	free_extent_buffer_stale(sb);
 	return ret;
-
-out_short_read:
-	btrfs_err(fs_info, "sys_array too short to read %u bytes at offset %u",
-			len, cur_offset);
-	clear_extent_buffer_uptodate(sb);
-	free_extent_buffer_stale(sb);
-	return -EIO;
 }
 
 /*
@@ -7568,8 +7610,6 @@ int btrfs_init_devices_late(struct btrfs_fs_info *fs_info)
 	struct btrfs_device *device;
 	int ret = 0;
 
-	fs_devices->fs_info = fs_info;
-
 	mutex_lock(&fs_devices->device_list_mutex);
 	list_for_each_entry(device, &fs_devices->devices, dev_list)
 		device->fs_info = fs_info;
@@ -7745,8 +7785,6 @@ static int update_dev_stat_item(struct btrfs_trans_handle *trans,
 	for (i = 0; i < BTRFS_DEV_STAT_VALUES_MAX; i++)
 		btrfs_set_dev_stats_value(eb, ptr, i,
 					  btrfs_dev_stat_read(device, i));
-	btrfs_mark_buffer_dirty(trans, eb);
-
 out:
 	btrfs_free_path(path);
 	return ret;
diff --git a/fs/btrfs/volumes.h b/fs/btrfs/volumes.h
index 3a416b1..120f65e 100644
--- a/fs/btrfs/volumes.h
+++ b/fs/btrfs/volumes.h
@@ -296,6 +296,9 @@ enum btrfs_chunk_allocation_policy {
 	BTRFS_CHUNK_ALLOC_ZONED,
 };
 
+#define BTRFS_DEFAULT_RR_MIN_CONTIG_READ	(SZ_256K)
+/* Keep in sync with raid_attr table, current maximum is RAID1C4. */
+#define BTRFS_RAID1_MAX_MIRRORS			(4)
 /*
  * Read policies for mirrored block group profiles, read picks the stripe based
  * on these policies.
@@ -303,6 +306,12 @@ enum btrfs_chunk_allocation_policy {
 enum btrfs_read_policy {
 	/* Use process PID to choose the stripe */
 	BTRFS_READ_POLICY_PID,
+#ifdef CONFIG_BTRFS_EXPERIMENTAL
+	/* Balancing RAID1 reads across all striped devices (round-robin). */
+	BTRFS_READ_POLICY_RR,
+	/* Read from a specific device. */
+	BTRFS_READ_POLICY_DEVID,
+#endif
 	BTRFS_NR_READ_POLICY,
 };
 
@@ -417,6 +426,8 @@ struct btrfs_fs_devices {
 	bool seeding;
 	/* The mount needs to use a randomly generated fsid. */
 	bool temp_fsid;
+	/* Enable/disable the filesystem stats tracking. */
+	bool collect_fs_stats;
 
 	struct btrfs_fs_info *fs_info;
 	/* sysfs kobjects */
@@ -431,6 +442,15 @@ struct btrfs_fs_devices {
 	enum btrfs_read_policy read_policy;
 
 #ifdef CONFIG_BTRFS_EXPERIMENTAL
+	/*
+	 * Minimum contiguous reads before switching to next device, the unit
+	 * is one block/sectorsize.
+	 */
+	u32 rr_min_contig_read;
+
+	/* Device to be used for reading in case of RAID1. */
+	u64 read_devid;
+
 	/* Checksum mode - offload it or do it synchronously. */
 	enum btrfs_offload_csum_mode offload_csum_mode;
 #endif
@@ -485,6 +505,7 @@ struct btrfs_io_context {
 	struct bio *orig_bio;
 	atomic_t error;
 	u16 max_errors;
+	bool use_rst;
 
 	u64 logical;
 	u64 size;
diff --git a/fs/btrfs/xattr.c b/fs/btrfs/xattr.c
index bc18710..3e0edbc 100644
--- a/fs/btrfs/xattr.c
+++ b/fs/btrfs/xattr.c
@@ -204,7 +204,6 @@ int btrfs_setxattr(struct btrfs_trans_handle *trans, struct inode *inode,
 		btrfs_set_dir_data_len(leaf, di, size);
 		data_ptr = ((unsigned long)(di + 1)) + name_len;
 		write_extent_buffer(leaf, value, data_ptr, size);
-		btrfs_mark_buffer_dirty(trans, leaf);
 	} else {
 		/*
 		 * Insert, and we had space for the xattr, so path->slots[0] is
diff --git a/fs/btrfs/zoned.c b/fs/btrfs/zoned.c
index df905ae..73e0aa9 100644
--- a/fs/btrfs/zoned.c
+++ b/fs/btrfs/zoned.c
@@ -2652,3 +2652,127 @@ void btrfs_check_active_zone_reservation(struct btrfs_fs_info *fs_info)
 	}
 	spin_unlock(&fs_info->zone_active_bgs_lock);
 }
+
+/*
+ * Reset the zones of unused block groups from @space_info->bytes_zone_unusable.
+ *
+ * @space_info:	the space to work on
+ * @num_bytes:	targeting reclaim bytes
+ *
+ * This one resets the zones of a block group, so we can reuse the region
+ * without removing the block group. On the other hand, btrfs_delete_unused_bgs()
+ * just removes a block group and frees up the underlying zones. So, we still
+ * need to allocate a new block group to reuse the zones.
+ *
+ * Resetting is faster than deleting/recreating a block group. It is similar
+ * to freeing the logical space on the regular mode. However, we cannot change
+ * the block group's profile with this operation.
+ */
+int btrfs_reset_unused_block_groups(struct btrfs_space_info *space_info, u64 num_bytes)
+{
+	struct btrfs_fs_info *fs_info = space_info->fs_info;
+	const sector_t zone_size_sectors = fs_info->zone_size >> SECTOR_SHIFT;
+
+	if (!btrfs_is_zoned(fs_info))
+		return 0;
+
+	while (num_bytes > 0) {
+		struct btrfs_chunk_map *map;
+		struct btrfs_block_group *bg = NULL;
+		bool found = false;
+		u64 reclaimed = 0;
+
+		/*
+		 * Here, we choose a fully zone_unusable block group. It's
+		 * technically possible to reset a partly zone_unusable block
+		 * group, which still has some free space left. However,
+		 * handling that needs to cope with the allocation side, which
+		 * makes the logic more complex. So, let's handle the easy case
+		 * for now.
+		 */
+		spin_lock(&fs_info->unused_bgs_lock);
+		list_for_each_entry(bg, &fs_info->unused_bgs, bg_list) {
+			if ((bg->flags & BTRFS_BLOCK_GROUP_TYPE_MASK) != space_info->flags)
+				continue;
+
+			/*
+			 * Use trylock to avoid locking order violation. In
+			 * btrfs_reclaim_bgs_work(), the lock order is
+			 * &bg->lock -> &fs_info->unused_bgs_lock. We skip a
+			 * block group if we cannot take its lock.
+			 */
+			if (!spin_trylock(&bg->lock))
+				continue;
+			if (btrfs_is_block_group_used(bg) || bg->zone_unusable < bg->length) {
+				spin_unlock(&bg->lock);
+				continue;
+			}
+			spin_unlock(&bg->lock);
+			found = true;
+			break;
+		}
+		if (!found) {
+			spin_unlock(&fs_info->unused_bgs_lock);
+			return 0;
+		}
+
+		list_del_init(&bg->bg_list);
+		btrfs_put_block_group(bg);
+		spin_unlock(&fs_info->unused_bgs_lock);
+
+		/*
+		 * Since the block group is fully zone_unusable and we cannot
+		 * allocate from this block group anymore, we don't need to set
+		 * this block group read-only.
+		 */
+
+		down_read(&fs_info->dev_replace.rwsem);
+		map = bg->physical_map;
+		for (int i = 0; i < map->num_stripes; i++) {
+			struct btrfs_io_stripe *stripe = &map->stripes[i];
+			unsigned int nofs_flags;
+			int ret;
+
+			nofs_flags = memalloc_nofs_save();
+			ret = blkdev_zone_mgmt(stripe->dev->bdev, REQ_OP_ZONE_RESET,
+					       stripe->physical >> SECTOR_SHIFT,
+					       zone_size_sectors);
+			memalloc_nofs_restore(nofs_flags);
+
+			if (ret) {
+				up_read(&fs_info->dev_replace.rwsem);
+				return ret;
+			}
+		}
+		up_read(&fs_info->dev_replace.rwsem);
+
+		spin_lock(&space_info->lock);
+		spin_lock(&bg->lock);
+		ASSERT(!btrfs_is_block_group_used(bg));
+		if (bg->ro) {
+			spin_unlock(&bg->lock);
+			spin_unlock(&space_info->lock);
+			continue;
+		}
+
+		reclaimed = bg->alloc_offset;
+		bg->zone_unusable = bg->length - bg->zone_capacity;
+		bg->alloc_offset = 0;
+		/*
+		 * This holds because we currently reset fully used then freed
+		 * block group.
+		 */
+		ASSERT(reclaimed == bg->zone_capacity);
+		bg->free_space_ctl->free_space += reclaimed;
+		space_info->bytes_zone_unusable -= reclaimed;
+		spin_unlock(&bg->lock);
+		btrfs_return_free_space(space_info, reclaimed);
+		spin_unlock(&space_info->lock);
+
+		if (num_bytes <= reclaimed)
+			break;
+		num_bytes -= reclaimed;
+	}
+
+	return 0;
+}
diff --git a/fs/btrfs/zoned.h b/fs/btrfs/zoned.h
index 7612e65..9672bf4 100644
--- a/fs/btrfs/zoned.h
+++ b/fs/btrfs/zoned.h
@@ -96,6 +96,7 @@ int btrfs_zone_finish_one_bg(struct btrfs_fs_info *fs_info);
 int btrfs_zoned_activate_one_bg(struct btrfs_fs_info *fs_info,
 				struct btrfs_space_info *space_info, bool do_finish);
 void btrfs_check_active_zone_reservation(struct btrfs_fs_info *fs_info);
+int btrfs_reset_unused_block_groups(struct btrfs_space_info *space_info, u64 num_bytes);
 #else /* CONFIG_BLK_DEV_ZONED */
 
 static inline int btrfs_get_dev_zone_info_all_devices(struct btrfs_fs_info *fs_info)
@@ -265,6 +266,12 @@ static inline int btrfs_zoned_activate_one_bg(struct btrfs_fs_info *fs_info,
 
 static inline void btrfs_check_active_zone_reservation(struct btrfs_fs_info *fs_info) { }
 
+static inline int btrfs_reset_unused_block_groups(struct btrfs_space_info *space_info,
+						  u64 num_bytes)
+{
+	return 0;
+}
+
 #endif
 
 static inline bool btrfs_dev_is_sequential(struct btrfs_device *device, u64 pos)
diff --git a/include/linux/rbtree.h b/include/linux/rbtree.h
index 7c173aa6..8d2ba37 100644
--- a/include/linux/rbtree.h
+++ b/include/linux/rbtree.h
@@ -211,6 +211,43 @@ rb_add(struct rb_node *node, struct rb_root *tree,
 }
 
 /**
+ * rb_find_add_cached() - find equivalent @node in @tree, or add @node
+ * @node: node to look-for / insert
+ * @tree: tree to search / modify
+ * @cmp: operator defining the node order
+ *
+ * Returns the rb_node matching @node, or NULL when no match is found and @node
+ * is inserted.
+ */
+static __always_inline struct rb_node *
+rb_find_add_cached(struct rb_node *node, struct rb_root_cached *tree,
+	    int (*cmp)(const struct rb_node *new, const struct rb_node *exist))
+{
+	bool leftmost = true;
+	struct rb_node **link = &tree->rb_root.rb_node;
+	struct rb_node *parent = NULL;
+	int c;
+
+	while (*link) {
+		parent = *link;
+		c = cmp(node, parent);
+
+		if (c < 0) {
+			link = &parent->rb_left;
+		} else if (c > 0) {
+			link = &parent->rb_right;
+			leftmost = false;
+		} else {
+			return parent;
+		}
+	}
+
+	rb_link_node(node, parent, link);
+	rb_insert_color_cached(node, tree, leftmost);
+	return NULL;
+}
+
+/**
  * rb_find_add() - find equivalent @node in @tree, or add @node
  * @node: node to look-for / insert
  * @tree: tree to search / modify
diff --git a/include/trace/events/btrfs.h b/include/trace/events/btrfs.h
index 4df93ca..549ab3b 100644
--- a/include/trace/events/btrfs.h
+++ b/include/trace/events/btrfs.h
@@ -100,7 +100,8 @@ struct find_free_extent_ctl;
 	EM( ALLOC_CHUNK,		"ALLOC_CHUNK")			\
 	EM( ALLOC_CHUNK_FORCE,		"ALLOC_CHUNK_FORCE")		\
 	EM( RUN_DELAYED_IPUTS,		"RUN_DELAYED_IPUTS")		\
-	EMe(COMMIT_TRANS,		"COMMIT_TRANS")
+	EM( COMMIT_TRANS,		"COMMIT_TRANS")			\
+	EMe(RESET_ZONES,		"RESET_ZONES")
 
 /*
  * First define the enums in the above macros to be exported to userspace via