diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c
index e4fad77..407830d 100644
--- a/fs/btrfs/disk-io.c
+++ b/fs/btrfs/disk-io.c
@@ -3594,7 +3594,6 @@ int __cold open_ctree(struct super_block *sb, struct btrfs_fs_devices *fs_device
 		}
 	}
 
-	btrfs_zoned_reserve_data_reloc_bg(fs_info);
 	btrfs_free_zone_cache(fs_info);
 
 	btrfs_check_active_zone_reservation(fs_info);
@@ -3622,6 +3621,12 @@ int __cold open_ctree(struct super_block *sb, struct btrfs_fs_devices *fs_device
 		goto fail_cleaner;
 	}
 
+	/*
+	 * Starts a transaction, must be called after the transaction kthread
+	 * is initialized.
+	 */
+	btrfs_zoned_reserve_data_reloc_bg(fs_info);
+
 	ret = btrfs_read_qgroup_config(fs_info);
 	if (ret)
 		goto fail_trans_kthread;
diff --git a/fs/btrfs/extent_io.c b/fs/btrfs/extent_io.c
index 744a1ff..5f97a3d 100644
--- a/fs/btrfs/extent_io.c
+++ b/fs/btrfs/extent_io.c
@@ -4507,6 +4507,7 @@ static int try_release_subpage_extent_buffer(struct folio *folio)
 		 */
 		if (!test_and_clear_bit(EXTENT_BUFFER_TREE_REF, &eb->bflags)) {
 			spin_unlock(&eb->refs_lock);
+			rcu_read_lock();
 			break;
 		}
 
diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c
index a11fcc9..a6da984 100644
--- a/fs/btrfs/inode.c
+++ b/fs/btrfs/inode.c
@@ -6612,6 +6612,25 @@ int btrfs_create_new_inode(struct btrfs_trans_handle *trans,
 	int ret;
 	bool xa_reserved = false;
 
+	if (!args->orphan && !args->subvol) {
+		/*
+		 * Before anything else, check if we can add the name to the
+		 * parent directory. We want to avoid a dir item overflow in
+		 * case we have an existing dir item due to existing name
+		 * hash collisions. We do this check here before we call
+		 * btrfs_add_link() down below so that we can avoid a
+		 * transaction abort (which could be exploited by malicious
+		 * users).
+		 *
+		 * For subvolumes we already do this in btrfs_mksubvol().
+		 */
+		ret = btrfs_check_dir_item_collision(BTRFS_I(dir)->root,
+						     btrfs_ino(BTRFS_I(dir)),
+						     name);
+		if (ret < 0)
+			return ret;
+	}
+
 	path = btrfs_alloc_path();
 	if (!path)
 		return -ENOMEM;
diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c
index a1fd44c..b805dd9 100644
--- a/fs/btrfs/ioctl.c
+++ b/fs/btrfs/ioctl.c
@@ -672,6 +672,13 @@ static noinline int create_subvol(struct mnt_idmap *idmap,
 		goto out;
 	}
 
+	/*
+	 * Subvolumes have orphans cleaned on first dentry lookup. A new
+	 * subvolume cannot have any orphans, so we should set the bit before we
+	 * add the subvolume dentry to the dentry cache, so that it is in the
+	 * same state as a subvolume after first lookup.
+	 */
+	set_bit(BTRFS_ROOT_ORPHAN_CLEANUP, &new_root->state);
 	d_instantiate_new(dentry, new_inode_args.inode);
 	new_inode_args.inode = NULL;
 
@@ -3852,6 +3859,25 @@ static long _btrfs_ioctl_set_received_subvol(struct file *file,
 		goto out;
 	}
 
+	received_uuid_changed = memcmp(root_item->received_uuid, sa->uuid,
+				       BTRFS_UUID_SIZE);
+
+	/*
+	 * Before we attempt to add the new received uuid, check if we have room
+	 * for it in case there's already an item. If the size of the existing
+	 * item plus this root's ID (u64) exceeds the maximum item size, we can
+	 * return here without the need to abort a transaction. If we don't do
+	 * this check, the btrfs_uuid_tree_add() call below would fail with
+	 * -EOVERFLOW and result in a transaction abort. Malicious users could
+	 * exploit this to turn the fs into RO mode.
+	 */
+	if (received_uuid_changed && !btrfs_is_empty_uuid(sa->uuid)) {
+		ret = btrfs_uuid_tree_check_overflow(fs_info, sa->uuid,
+						     BTRFS_UUID_KEY_RECEIVED_SUBVOL);
+		if (ret < 0)
+			goto out;
+	}
+
 	/*
 	 * 1 - root item
 	 * 2 - uuid items (received uuid + subvol uuid)
@@ -3867,15 +3893,12 @@ static long _btrfs_ioctl_set_received_subvol(struct file *file,
 	sa->rtime.sec = ct.tv_sec;
 	sa->rtime.nsec = ct.tv_nsec;
 
-	received_uuid_changed = memcmp(root_item->received_uuid, sa->uuid,
-				       BTRFS_UUID_SIZE);
 	if (received_uuid_changed &&
 	    !btrfs_is_empty_uuid(root_item->received_uuid)) {
 		ret = btrfs_uuid_tree_remove(trans, root_item->received_uuid,
 					  BTRFS_UUID_KEY_RECEIVED_SUBVOL,
 					  btrfs_root_id(root));
 		if (unlikely(ret && ret != -ENOENT)) {
-		        btrfs_abort_transaction(trans, ret);
 		        btrfs_end_transaction(trans);
 		        goto out;
 		}
@@ -3890,7 +3913,8 @@ static long _btrfs_ioctl_set_received_subvol(struct file *file,
 
 	ret = btrfs_update_root(trans, fs_info->tree_root,
 				&root->root_key, &root->root_item);
-	if (ret < 0) {
+	if (unlikely(ret < 0)) {
+		btrfs_abort_transaction(trans, ret);
 		btrfs_end_transaction(trans);
 		goto out;
 	}
diff --git a/fs/btrfs/messages.h b/fs/btrfs/messages.h
index 943e539..c8e92ef 100644
--- a/fs/btrfs/messages.h
+++ b/fs/btrfs/messages.h
@@ -31,9 +31,6 @@ void _btrfs_printk(const struct btrfs_fs_info *fs_info, unsigned int level, cons
 #define btrfs_printk_in_rcu(fs_info, level, fmt, args...)		\
 	btrfs_no_printk(fs_info, fmt, ##args)
 
-#define btrfs_printk_in_rcu(fs_info, level, fmt, args...)		\
-	btrfs_no_printk(fs_info, fmt, ##args)
-
 #define btrfs_printk_rl_in_rcu(fs_info, level, fmt, args...)		\
 	btrfs_no_printk(fs_info, fmt, ##args)
 
diff --git a/fs/btrfs/print-tree.c b/fs/btrfs/print-tree.c
index f189bf0..b7dfe87 100644
--- a/fs/btrfs/print-tree.c
+++ b/fs/btrfs/print-tree.c
@@ -38,6 +38,7 @@ static const struct root_name_map root_map[] = {
 	{ BTRFS_BLOCK_GROUP_TREE_OBJECTID,	"BLOCK_GROUP_TREE"	},
 	{ BTRFS_DATA_RELOC_TREE_OBJECTID,	"DATA_RELOC_TREE"	},
 	{ BTRFS_RAID_STRIPE_TREE_OBJECTID,	"RAID_STRIPE_TREE"	},
+	{ BTRFS_REMAP_TREE_OBJECTID,		"REMAP_TREE"		},
 };
 
 const char *btrfs_root_name(const struct btrfs_key *key, char *buf)
@@ -415,6 +416,9 @@ static void key_type_string(const struct btrfs_key *key, char *buf, int buf_size
 		[BTRFS_UUID_KEY_SUBVOL]			= "UUID_KEY_SUBVOL",
 		[BTRFS_UUID_KEY_RECEIVED_SUBVOL]	= "UUID_KEY_RECEIVED_SUBVOL",
 		[BTRFS_RAID_STRIPE_KEY]			= "RAID_STRIPE",
+		[BTRFS_IDENTITY_REMAP_KEY]		= "IDENTITY_REMAP",
+		[BTRFS_REMAP_KEY]			= "REMAP",
+		[BTRFS_REMAP_BACKREF_KEY]		= "REMAP_BACKREF",
 	};
 
 	if (key->type == 0 && key->objectid == BTRFS_FREE_SPACE_OBJECTID)
@@ -435,6 +439,7 @@ void btrfs_print_leaf(const struct extent_buffer *l)
 	struct btrfs_extent_data_ref *dref;
 	struct btrfs_shared_data_ref *sref;
 	struct btrfs_dev_extent *dev_extent;
+	struct btrfs_remap_item *remap;
 	struct btrfs_key key;
 
 	if (!l)
@@ -569,6 +574,11 @@ void btrfs_print_leaf(const struct extent_buffer *l)
 			print_raid_stripe_key(l, btrfs_item_size(l, i),
 				btrfs_item_ptr(l, i, struct btrfs_stripe_extent));
 			break;
+		case BTRFS_REMAP_KEY:
+		case BTRFS_REMAP_BACKREF_KEY:
+			remap = btrfs_item_ptr(l, i, struct btrfs_remap_item);
+			pr_info("\t\taddress %llu\n", btrfs_remap_address(l, remap));
+			break;
 		}
 	}
 }
diff --git a/fs/btrfs/relocation.c b/fs/btrfs/relocation.c
index a330d86..b2343ae 100644
--- a/fs/btrfs/relocation.c
+++ b/fs/btrfs/relocation.c
@@ -4399,6 +4399,8 @@ static int move_existing_remaps(struct btrfs_fs_info *fs_info,
 
 				leaf = path->nodes[0];
 			}
+
+			btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
 		}
 
 		remap = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_remap_item);
diff --git a/fs/btrfs/space-info.c b/fs/btrfs/space-info.c
index 52a267a..87cbc05 100644
--- a/fs/btrfs/space-info.c
+++ b/fs/btrfs/space-info.c
@@ -2194,8 +2194,11 @@ void btrfs_reclaim_sweep(const struct btrfs_fs_info *fs_info)
 		if (!btrfs_should_periodic_reclaim(space_info))
 			continue;
 		for (raid = 0; raid < BTRFS_NR_RAID_TYPES; raid++) {
-			if (do_reclaim_sweep(space_info, raid))
+			if (do_reclaim_sweep(space_info, raid)) {
+				spin_lock(&space_info->lock);
 				btrfs_set_periodic_reclaim_ready(space_info, false);
+				spin_unlock(&space_info->lock);
+			}
 		}
 	}
 }
diff --git a/fs/btrfs/transaction.c b/fs/btrfs/transaction.c
index 7ef8c9b..8dd77c4 100644
--- a/fs/btrfs/transaction.c
+++ b/fs/btrfs/transaction.c
@@ -1905,6 +1905,22 @@ static noinline int create_pending_snapshot(struct btrfs_trans_handle *trans,
 		ret = btrfs_uuid_tree_add(trans, new_root_item->received_uuid,
 					  BTRFS_UUID_KEY_RECEIVED_SUBVOL,
 					  objectid);
+		/*
+		 * We are creating of lot of snapshots of the same root that was
+		 * received (has a received UUID) and reached a leaf's limit for
+		 * an item. We can safely ignore this and avoid a transaction
+		 * abort. A deletion of this snapshot will still work since we
+		 * ignore if an item with a BTRFS_UUID_KEY_RECEIVED_SUBVOL key
+		 * is missing (see btrfs_delete_subvolume()). Send/receive will
+		 * work too since it peeks the first root id from the existing
+		 * item (it could peek any), and in case it's missing it
+		 * falls back to search by BTRFS_UUID_KEY_SUBVOL keys.
+		 * Creation of a snapshot does not require CAP_SYS_ADMIN, so
+		 * we don't want users triggering transaction aborts, either
+		 * intentionally or not.
+		 */
+		if (ret == -EOVERFLOW)
+			ret = 0;
 		if (unlikely(ret && ret != -EEXIST)) {
 			btrfs_abort_transaction(trans, ret);
 			goto fail;
diff --git a/fs/btrfs/uuid-tree.c b/fs/btrfs/uuid-tree.c
index f24c14b..43c17a1 100644
--- a/fs/btrfs/uuid-tree.c
+++ b/fs/btrfs/uuid-tree.c
@@ -199,6 +199,44 @@ int btrfs_uuid_tree_remove(struct btrfs_trans_handle *trans, const u8 *uuid, u8 
 	return 0;
 }
 
+/*
+ * Check if we can add one root ID to a UUID key.
+ * If the key does not yet exists, we can, otherwise only if extended item does
+ * not exceeds the maximum item size permitted by the leaf size.
+ *
+ * Returns 0 on success, negative value on error.
+ */
+int btrfs_uuid_tree_check_overflow(struct btrfs_fs_info *fs_info,
+				   const u8 *uuid, u8 type)
+{
+	BTRFS_PATH_AUTO_FREE(path);
+	int ret;
+	u32 item_size;
+	struct btrfs_key key;
+
+	if (WARN_ON_ONCE(!fs_info->uuid_root))
+		return -EINVAL;
+
+	path = btrfs_alloc_path();
+	if (!path)
+		return -ENOMEM;
+
+	btrfs_uuid_to_key(uuid, type, &key);
+	ret = btrfs_search_slot(NULL, fs_info->uuid_root, &key, path, 0, 0);
+	if (ret < 0)
+		return ret;
+	if (ret > 0)
+		return 0;
+
+	item_size = btrfs_item_size(path->nodes[0], path->slots[0]);
+
+	if (sizeof(struct btrfs_item) + item_size + sizeof(u64) >
+	    BTRFS_LEAF_DATA_SIZE(fs_info))
+		return -EOVERFLOW;
+
+	return 0;
+}
+
 static int btrfs_uuid_iter_rem(struct btrfs_root *uuid_root, u8 *uuid, u8 type,
 			       u64 subid)
 {
diff --git a/fs/btrfs/uuid-tree.h b/fs/btrfs/uuid-tree.h
index c60ad20..02b235a 100644
--- a/fs/btrfs/uuid-tree.h
+++ b/fs/btrfs/uuid-tree.h
@@ -12,6 +12,8 @@ int btrfs_uuid_tree_add(struct btrfs_trans_handle *trans, const u8 *uuid, u8 typ
 			u64 subid);
 int btrfs_uuid_tree_remove(struct btrfs_trans_handle *trans, const u8 *uuid, u8 type,
 			u64 subid);
+int btrfs_uuid_tree_check_overflow(struct btrfs_fs_info *fs_info,
+				   const u8 *uuid, u8 type);
 int btrfs_uuid_tree_iterate(struct btrfs_fs_info *fs_info);
 int btrfs_create_uuid_tree(struct btrfs_fs_info *fs_info);
 int btrfs_uuid_scan_kthread(void *data);