v4.19.13 snapshot.
diff --git a/fs/btrfs/tests/btrfs-tests.c b/fs/btrfs/tests/btrfs-tests.c
new file mode 100644
index 0000000..db72b3b
--- /dev/null
+++ b/fs/btrfs/tests/btrfs-tests.c
@@ -0,0 +1,274 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (C) 2013 Fusion IO.  All rights reserved.
+ */
+
+#include <linux/fs.h>
+#include <linux/mount.h>
+#include <linux/magic.h>
+#include "btrfs-tests.h"
+#include "../ctree.h"
+#include "../free-space-cache.h"
+#include "../free-space-tree.h"
+#include "../transaction.h"
+#include "../volumes.h"
+#include "../disk-io.h"
+#include "../qgroup.h"
+
+static struct vfsmount *test_mnt = NULL;
+
+static const struct super_operations btrfs_test_super_ops = {
+	.alloc_inode	= btrfs_alloc_inode,
+	.destroy_inode	= btrfs_test_destroy_inode,
+};
+
+static struct dentry *btrfs_test_mount(struct file_system_type *fs_type,
+				       int flags, const char *dev_name,
+				       void *data)
+{
+	return mount_pseudo(fs_type, "btrfs_test:", &btrfs_test_super_ops,
+			    NULL, BTRFS_TEST_MAGIC);
+}
+
+static struct file_system_type test_type = {
+	.name		= "btrfs_test_fs",
+	.mount		= btrfs_test_mount,
+	.kill_sb	= kill_anon_super,
+};
+
+struct inode *btrfs_new_test_inode(void)
+{
+	return new_inode(test_mnt->mnt_sb);
+}
+
+static int btrfs_init_test_fs(void)
+{
+	int ret;
+
+	ret = register_filesystem(&test_type);
+	if (ret) {
+		printk(KERN_ERR "btrfs: cannot register test file system\n");
+		return ret;
+	}
+
+	test_mnt = kern_mount(&test_type);
+	if (IS_ERR(test_mnt)) {
+		printk(KERN_ERR "btrfs: cannot mount test file system\n");
+		unregister_filesystem(&test_type);
+		return PTR_ERR(test_mnt);
+	}
+	return 0;
+}
+
+static void btrfs_destroy_test_fs(void)
+{
+	kern_unmount(test_mnt);
+	unregister_filesystem(&test_type);
+}
+
+struct btrfs_fs_info *btrfs_alloc_dummy_fs_info(u32 nodesize, u32 sectorsize)
+{
+	struct btrfs_fs_info *fs_info = kzalloc(sizeof(struct btrfs_fs_info),
+						GFP_KERNEL);
+
+	if (!fs_info)
+		return fs_info;
+	fs_info->fs_devices = kzalloc(sizeof(struct btrfs_fs_devices),
+				      GFP_KERNEL);
+	if (!fs_info->fs_devices) {
+		kfree(fs_info);
+		return NULL;
+	}
+	fs_info->super_copy = kzalloc(sizeof(struct btrfs_super_block),
+				      GFP_KERNEL);
+	if (!fs_info->super_copy) {
+		kfree(fs_info->fs_devices);
+		kfree(fs_info);
+		return NULL;
+	}
+
+	fs_info->nodesize = nodesize;
+	fs_info->sectorsize = sectorsize;
+
+	if (init_srcu_struct(&fs_info->subvol_srcu)) {
+		kfree(fs_info->fs_devices);
+		kfree(fs_info->super_copy);
+		kfree(fs_info);
+		return NULL;
+	}
+
+	spin_lock_init(&fs_info->buffer_lock);
+	spin_lock_init(&fs_info->qgroup_lock);
+	spin_lock_init(&fs_info->qgroup_op_lock);
+	spin_lock_init(&fs_info->super_lock);
+	spin_lock_init(&fs_info->fs_roots_radix_lock);
+	spin_lock_init(&fs_info->tree_mod_seq_lock);
+	mutex_init(&fs_info->qgroup_ioctl_lock);
+	mutex_init(&fs_info->qgroup_rescan_lock);
+	rwlock_init(&fs_info->tree_mod_log_lock);
+	fs_info->running_transaction = NULL;
+	fs_info->qgroup_tree = RB_ROOT;
+	fs_info->qgroup_ulist = NULL;
+	atomic64_set(&fs_info->tree_mod_seq, 0);
+	INIT_LIST_HEAD(&fs_info->dirty_qgroups);
+	INIT_LIST_HEAD(&fs_info->dead_roots);
+	INIT_LIST_HEAD(&fs_info->tree_mod_seq_list);
+	INIT_RADIX_TREE(&fs_info->buffer_radix, GFP_ATOMIC);
+	INIT_RADIX_TREE(&fs_info->fs_roots_radix, GFP_ATOMIC);
+	extent_io_tree_init(&fs_info->freed_extents[0], NULL);
+	extent_io_tree_init(&fs_info->freed_extents[1], NULL);
+	fs_info->pinned_extents = &fs_info->freed_extents[0];
+	set_bit(BTRFS_FS_STATE_DUMMY_FS_INFO, &fs_info->fs_state);
+
+	test_mnt->mnt_sb->s_fs_info = fs_info;
+
+	return fs_info;
+}
+
+void btrfs_free_dummy_fs_info(struct btrfs_fs_info *fs_info)
+{
+	struct radix_tree_iter iter;
+	void **slot;
+
+	if (!fs_info)
+		return;
+
+	if (WARN_ON(!test_bit(BTRFS_FS_STATE_DUMMY_FS_INFO,
+			      &fs_info->fs_state)))
+		return;
+
+	test_mnt->mnt_sb->s_fs_info = NULL;
+
+	spin_lock(&fs_info->buffer_lock);
+	radix_tree_for_each_slot(slot, &fs_info->buffer_radix, &iter, 0) {
+		struct extent_buffer *eb;
+
+		eb = radix_tree_deref_slot_protected(slot, &fs_info->buffer_lock);
+		if (!eb)
+			continue;
+		/* Shouldn't happen but that kind of thinking creates CVE's */
+		if (radix_tree_exception(eb)) {
+			if (radix_tree_deref_retry(eb))
+				slot = radix_tree_iter_retry(&iter);
+			continue;
+		}
+		slot = radix_tree_iter_resume(slot, &iter);
+		spin_unlock(&fs_info->buffer_lock);
+		free_extent_buffer_stale(eb);
+		spin_lock(&fs_info->buffer_lock);
+	}
+	spin_unlock(&fs_info->buffer_lock);
+
+	btrfs_free_qgroup_config(fs_info);
+	btrfs_free_fs_roots(fs_info);
+	cleanup_srcu_struct(&fs_info->subvol_srcu);
+	kfree(fs_info->super_copy);
+	kfree(fs_info->fs_devices);
+	kfree(fs_info);
+}
+
+void btrfs_free_dummy_root(struct btrfs_root *root)
+{
+	if (!root)
+		return;
+	/* Will be freed by btrfs_free_fs_roots */
+	if (WARN_ON(test_bit(BTRFS_ROOT_IN_RADIX, &root->state)))
+		return;
+	if (root->node)
+		free_extent_buffer(root->node);
+	kfree(root);
+}
+
+struct btrfs_block_group_cache *
+btrfs_alloc_dummy_block_group(struct btrfs_fs_info *fs_info,
+			      unsigned long length)
+{
+	struct btrfs_block_group_cache *cache;
+
+	cache = kzalloc(sizeof(*cache), GFP_KERNEL);
+	if (!cache)
+		return NULL;
+	cache->free_space_ctl = kzalloc(sizeof(*cache->free_space_ctl),
+					GFP_KERNEL);
+	if (!cache->free_space_ctl) {
+		kfree(cache);
+		return NULL;
+	}
+
+	cache->key.objectid = 0;
+	cache->key.offset = length;
+	cache->key.type = BTRFS_BLOCK_GROUP_ITEM_KEY;
+	cache->full_stripe_len = fs_info->sectorsize;
+	cache->fs_info = fs_info;
+
+	INIT_LIST_HEAD(&cache->list);
+	INIT_LIST_HEAD(&cache->cluster_list);
+	INIT_LIST_HEAD(&cache->bg_list);
+	btrfs_init_free_space_ctl(cache);
+	mutex_init(&cache->free_space_lock);
+
+	return cache;
+}
+
+void btrfs_free_dummy_block_group(struct btrfs_block_group_cache *cache)
+{
+	if (!cache)
+		return;
+	__btrfs_remove_free_space_cache(cache->free_space_ctl);
+	kfree(cache->free_space_ctl);
+	kfree(cache);
+}
+
+void btrfs_init_dummy_trans(struct btrfs_trans_handle *trans,
+			    struct btrfs_fs_info *fs_info)
+{
+	memset(trans, 0, sizeof(*trans));
+	trans->transid = 1;
+	trans->type = __TRANS_DUMMY;
+	trans->fs_info = fs_info;
+}
+
+int btrfs_run_sanity_tests(void)
+{
+	int ret, i;
+	u32 sectorsize, nodesize;
+	u32 test_sectorsize[] = {
+		PAGE_SIZE,
+	};
+	ret = btrfs_init_test_fs();
+	if (ret)
+		return ret;
+	for (i = 0; i < ARRAY_SIZE(test_sectorsize); i++) {
+		sectorsize = test_sectorsize[i];
+		for (nodesize = sectorsize;
+		     nodesize <= BTRFS_MAX_METADATA_BLOCKSIZE;
+		     nodesize <<= 1) {
+			pr_info("BTRFS: selftest: sectorsize: %u  nodesize: %u\n",
+				sectorsize, nodesize);
+			ret = btrfs_test_free_space_cache(sectorsize, nodesize);
+			if (ret)
+				goto out;
+			ret = btrfs_test_extent_buffer_operations(sectorsize,
+				nodesize);
+			if (ret)
+				goto out;
+			ret = btrfs_test_extent_io(sectorsize, nodesize);
+			if (ret)
+				goto out;
+			ret = btrfs_test_inodes(sectorsize, nodesize);
+			if (ret)
+				goto out;
+			ret = btrfs_test_qgroups(sectorsize, nodesize);
+			if (ret)
+				goto out;
+			ret = btrfs_test_free_space_tree(sectorsize, nodesize);
+			if (ret)
+				goto out;
+		}
+	}
+	ret = btrfs_test_extent_map();
+
+out:
+	btrfs_destroy_test_fs();
+	return ret;
+}