Fixed MTP to work with TWRP

fs/btrfs/tests/btrfs-tests.c

@@ -0,0 +1,171 @@
+/*
+ * Copyright (C) 2013 Fusion IO.  All rights reserved.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public
+ * License v2 as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public
+ * License along with this program; if not, write to the
+ * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
+ * Boston, MA 021110-1307, USA.
+ */
+
+#include <linux/fs.h>
+#include <linux/mount.h>
+#include <linux/magic.h>
+#include "btrfs-tests.h"
+#include "../ctree.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);
+}
+
+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 ret;
+	}
+	return 0;
+}
+
+void btrfs_destroy_test_fs(void)
+{
+	kern_unmount(test_mnt);
+	unregister_filesystem(&test_type);
+}
+
+struct btrfs_fs_info *btrfs_alloc_dummy_fs_info(void)
+{
+	struct btrfs_fs_info *fs_info = kzalloc(sizeof(struct btrfs_fs_info),
+						GFP_NOFS);
+
+	if (!fs_info)
+		return fs_info;
+	fs_info->fs_devices = kzalloc(sizeof(struct btrfs_fs_devices),
+				      GFP_NOFS);
+	if (!fs_info->fs_devices) {
+		kfree(fs_info);
+		return NULL;
+	}
+	fs_info->super_copy = kzalloc(sizeof(struct btrfs_super_block),
+				      GFP_NOFS);
+	if (!fs_info->super_copy) {
+		kfree(fs_info->fs_devices);
+		kfree(fs_info);
+		return NULL;
+	}
+
+	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);
+	return fs_info;
+}
+
+static void btrfs_free_dummy_fs_info(struct btrfs_fs_info *fs_info)
+{
+	struct radix_tree_iter iter;
+	void **slot;
+
+	spin_lock(&fs_info->buffer_lock);
+restart:
+	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))
+				goto restart;
+			continue;
+		}
+		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;
+	if (root->node)
+		free_extent_buffer(root->node);
+	if (root->fs_info)
+		btrfs_free_dummy_fs_info(root->fs_info);
+	kfree(root);
+}
+

fs/btrfs/tests/btrfs-tests.h

@@ -0,0 +1,68 @@
+/*
+ * Copyright (C) 2013 Fusion IO.  All rights reserved.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public
+ * License v2 as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public
+ * License along with this program; if not, write to the
+ * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
+ * Boston, MA 021110-1307, USA.
+ */
+
+#ifndef __BTRFS_TESTS
+#define __BTRFS_TESTS
+
+#ifdef CONFIG_BTRFS_FS_RUN_SANITY_TESTS
+
+#define test_msg(fmt, ...) pr_info("BTRFS: selftest: " fmt, ##__VA_ARGS__)
+
+struct btrfs_root;
+
+int btrfs_test_free_space_cache(void);
+int btrfs_test_extent_buffer_operations(void);
+int btrfs_test_extent_io(void);
+int btrfs_test_inodes(void);
+int btrfs_test_qgroups(void);
+int btrfs_init_test_fs(void);
+void btrfs_destroy_test_fs(void);
+struct inode *btrfs_new_test_inode(void);
+struct btrfs_fs_info *btrfs_alloc_dummy_fs_info(void);
+void btrfs_free_dummy_root(struct btrfs_root *root);
+#else
+static inline int btrfs_test_free_space_cache(void)
+{
+	return 0;
+}
+static inline int btrfs_test_extent_buffer_operations(void)
+{
+	return 0;
+}
+static inline int btrfs_init_test_fs(void)
+{
+	return 0;
+}
+static inline void btrfs_destroy_test_fs(void)
+{
+}
+static inline int btrfs_test_extent_io(void)
+{
+	return 0;
+}
+static inline int btrfs_test_inodes(void)
+{
+	return 0;
+}
+static inline int btrfs_test_qgroups(void)
+{
+	return 0;
+}
+#endif
+
+#endif

fs/btrfs/tests/extent-buffer-tests.c

@@ -0,0 +1,229 @@
+/*
+ * Copyright (C) 2013 Fusion IO.  All rights reserved.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public
+ * License v2 as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public
+ * License along with this program; if not, write to the
+ * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
+ * Boston, MA 021110-1307, USA.
+ */
+
+#include <linux/slab.h>
+#include "btrfs-tests.h"
+#include "../ctree.h"
+#include "../extent_io.h"
+#include "../disk-io.h"
+
+static int test_btrfs_split_item(void)
+{
+	struct btrfs_path *path;
+	struct btrfs_root *root;
+	struct extent_buffer *eb;
+	struct btrfs_item *item;
+	char *value = "mary had a little lamb";
+	char *split1 = "mary had a little";
+	char *split2 = " lamb";
+	char *split3 = "mary";
+	char *split4 = " had a little";
+	char buf[32];
+	struct btrfs_key key;
+	u32 value_len = strlen(value);
+	int ret = 0;
+
+	test_msg("Running btrfs_split_item tests\n");
+
+	root = btrfs_alloc_dummy_root();
+	if (IS_ERR(root)) {
+		test_msg("Could not allocate root\n");
+		return PTR_ERR(root);
+	}
+
+	path = btrfs_alloc_path();
+	if (!path) {
+		test_msg("Could not allocate path\n");
+		kfree(root);
+		return -ENOMEM;
+	}
+
+	path->nodes[0] = eb = alloc_dummy_extent_buffer(0, 4096);
+	if (!eb) {
+		test_msg("Could not allocate dummy buffer\n");
+		ret = -ENOMEM;
+		goto out;
+	}
+	path->slots[0] = 0;
+
+	key.objectid = 0;
+	key.type = BTRFS_EXTENT_CSUM_KEY;
+	key.offset = 0;
+
+	setup_items_for_insert(root, path, &key, &value_len, value_len,
+			       value_len + sizeof(struct btrfs_item), 1);
+	item = btrfs_item_nr(0);
+	write_extent_buffer(eb, value, btrfs_item_ptr_offset(eb, 0),
+			    value_len);
+
+	key.offset = 3;
+
+	/*
+	 * Passing NULL trans here should be safe because we have plenty of
+	 * space in this leaf to split the item without having to split the
+	 * leaf.
+	 */
+	ret = btrfs_split_item(NULL, root, path, &key, 17);
+	if (ret) {
+		test_msg("Split item failed %d\n", ret);
+		goto out;
+	}
+
+	/*
+	 * Read the first slot, it should have the original key and contain only
+	 * 'mary had a little'
+	 */
+	btrfs_item_key_to_cpu(eb, &key, 0);
+	if (key.objectid != 0 || key.type != BTRFS_EXTENT_CSUM_KEY ||
+	    key.offset != 0) {
+		test_msg("Invalid key at slot 0\n");
+		ret = -EINVAL;
+		goto out;
+	}
+
+	item = btrfs_item_nr(0);
+	if (btrfs_item_size(eb, item) != strlen(split1)) {
+		test_msg("Invalid len in the first split\n");
+		ret = -EINVAL;
+		goto out;
+	}
+
+	read_extent_buffer(eb, buf, btrfs_item_ptr_offset(eb, 0),
+			   strlen(split1));
+	if (memcmp(buf, split1, strlen(split1))) {
+		test_msg("Data in the buffer doesn't match what it should "
+			 "in the first split have='%.*s' want '%s'\n",
+			 (int)strlen(split1), buf, split1);
+		ret = -EINVAL;
+		goto out;
+	}
+
+	btrfs_item_key_to_cpu(eb, &key, 1);
+	if (key.objectid != 0 || key.type != BTRFS_EXTENT_CSUM_KEY ||
+	    key.offset != 3) {
+		test_msg("Invalid key at slot 1\n");
+		ret = -EINVAL;
+		goto out;
+	}
+
+	item = btrfs_item_nr(1);
+	if (btrfs_item_size(eb, item) != strlen(split2)) {
+		test_msg("Invalid len in the second split\n");
+		ret = -EINVAL;
+		goto out;
+	}
+
+	read_extent_buffer(eb, buf, btrfs_item_ptr_offset(eb, 1),
+			   strlen(split2));
+	if (memcmp(buf, split2, strlen(split2))) {
+		test_msg("Data in the buffer doesn't match what it should "
+			 "in the second split\n");
+		ret = -EINVAL;
+		goto out;
+	}
+
+	key.offset = 1;
+	/* Do it again so we test memmoving the other items in the leaf */
+	ret = btrfs_split_item(NULL, root, path, &key, 4);
+	if (ret) {
+		test_msg("Second split item failed %d\n", ret);
+		goto out;
+	}
+
+	btrfs_item_key_to_cpu(eb, &key, 0);
+	if (key.objectid != 0 || key.type != BTRFS_EXTENT_CSUM_KEY ||
+	    key.offset != 0) {
+		test_msg("Invalid key at slot 0\n");
+		ret = -EINVAL;
+		goto out;
+	}
+
+	item = btrfs_item_nr(0);
+	if (btrfs_item_size(eb, item) != strlen(split3)) {
+		test_msg("Invalid len in the first split\n");
+		ret = -EINVAL;
+		goto out;
+	}
+
+	read_extent_buffer(eb, buf, btrfs_item_ptr_offset(eb, 0),
+			   strlen(split3));
+	if (memcmp(buf, split3, strlen(split3))) {
+		test_msg("Data in the buffer doesn't match what it should "
+			 "in the third split");
+		ret = -EINVAL;
+		goto out;
+	}
+
+	btrfs_item_key_to_cpu(eb, &key, 1);
+	if (key.objectid != 0 || key.type != BTRFS_EXTENT_CSUM_KEY ||
+	    key.offset != 1) {
+		test_msg("Invalid key at slot 1\n");
+		ret = -EINVAL;
+		goto out;
+	}
+
+	item = btrfs_item_nr(1);
+	if (btrfs_item_size(eb, item) != strlen(split4)) {
+		test_msg("Invalid len in the second split\n");
+		ret = -EINVAL;
+		goto out;
+	}
+
+	read_extent_buffer(eb, buf, btrfs_item_ptr_offset(eb, 1),
+			   strlen(split4));
+	if (memcmp(buf, split4, strlen(split4))) {
+		test_msg("Data in the buffer doesn't match what it should "
+			 "in the fourth split\n");
+		ret = -EINVAL;
+		goto out;
+	}
+
+	btrfs_item_key_to_cpu(eb, &key, 2);
+	if (key.objectid != 0 || key.type != BTRFS_EXTENT_CSUM_KEY ||
+	    key.offset != 3) {
+		test_msg("Invalid key at slot 2\n");
+		ret = -EINVAL;
+		goto out;
+	}
+
+	item = btrfs_item_nr(2);
+	if (btrfs_item_size(eb, item) != strlen(split2)) {
+		test_msg("Invalid len in the second split\n");
+		ret = -EINVAL;
+		goto out;
+	}
+
+	read_extent_buffer(eb, buf, btrfs_item_ptr_offset(eb, 2),
+			   strlen(split2));
+	if (memcmp(buf, split2, strlen(split2))) {
+		test_msg("Data in the buffer doesn't match what it should "
+			 "in the last chunk\n");
+		ret = -EINVAL;
+		goto out;
+	}
+out:
+	btrfs_free_path(path);
+	kfree(root);
+	return ret;
+}
+
+int btrfs_test_extent_buffer_operations(void)
+{
+	test_msg("Running extent buffer operation tests");
+	return test_btrfs_split_item();
+}

fs/btrfs/tests/extent-io-tests.c

@@ -0,0 +1,276 @@
+/*
+ * Copyright (C) 2013 Fusion IO.  All rights reserved.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public
+ * License v2 as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public
+ * License along with this program; if not, write to the
+ * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
+ * Boston, MA 021110-1307, USA.
+ */
+
+#include <linux/pagemap.h>
+#include <linux/sched.h>
+#include "btrfs-tests.h"
+#include "../extent_io.h"
+
+#define PROCESS_UNLOCK		(1 << 0)
+#define PROCESS_RELEASE		(1 << 1)
+#define PROCESS_TEST_LOCKED	(1 << 2)
+
+static noinline int process_page_range(struct inode *inode, u64 start, u64 end,
+				       unsigned long flags)
+{
+	int ret;
+	struct page *pages[16];
+	unsigned long index = start >> PAGE_CACHE_SHIFT;
+	unsigned long end_index = end >> PAGE_CACHE_SHIFT;
+	unsigned long nr_pages = end_index - index + 1;
+	int i;
+	int count = 0;
+	int loops = 0;
+
+	while (nr_pages > 0) {
+		ret = find_get_pages_contig(inode->i_mapping, index,
+				     min_t(unsigned long, nr_pages,
+				     ARRAY_SIZE(pages)), pages);
+		for (i = 0; i < ret; i++) {
+			if (flags & PROCESS_TEST_LOCKED &&
+			    !PageLocked(pages[i]))
+				count++;
+			if (flags & PROCESS_UNLOCK && PageLocked(pages[i]))
+				unlock_page(pages[i]);
+			page_cache_release(pages[i]);
+			if (flags & PROCESS_RELEASE)
+				page_cache_release(pages[i]);
+		}
+		nr_pages -= ret;
+		index += ret;
+		cond_resched();
+		loops++;
+		if (loops > 100000) {
+			printk(KERN_ERR "stuck in a loop, start %Lu, end %Lu, nr_pages %lu, ret %d\n", start, end, nr_pages, ret);
+			break;
+		}
+	}
+	return count;
+}
+
+static int test_find_delalloc(void)
+{
+	struct inode *inode;
+	struct extent_io_tree tmp;
+	struct page *page;
+	struct page *locked_page = NULL;
+	unsigned long index = 0;
+	u64 total_dirty = 256 * 1024 * 1024;
+	u64 max_bytes = 128 * 1024 * 1024;
+	u64 start, end, test_start;
+	u64 found;
+	int ret = -EINVAL;
+
+	inode = btrfs_new_test_inode();
+	if (!inode) {
+		test_msg("Failed to allocate test inode\n");
+		return -ENOMEM;
+	}
+
+	extent_io_tree_init(&tmp, &inode->i_data);
+
+	/*
+	 * First go through and create and mark all of our pages dirty, we pin
+	 * everything to make sure our pages don't get evicted and screw up our
+	 * test.
+	 */
+	for (index = 0; index < (total_dirty >> PAGE_CACHE_SHIFT); index++) {
+		page = find_or_create_page(inode->i_mapping, index, GFP_NOFS);
+		if (!page) {
+			test_msg("Failed to allocate test page\n");
+			ret = -ENOMEM;
+			goto out;
+		}
+		SetPageDirty(page);
+		if (index) {
+			unlock_page(page);
+		} else {
+			page_cache_get(page);
+			locked_page = page;
+		}
+	}
+
+	/* Test this scenario
+	 * |--- delalloc ---|
+	 * |---  search  ---|
+	 */
+	set_extent_delalloc(&tmp, 0, 4095, NULL, GFP_NOFS);
+	start = 0;
+	end = 0;
+	found = find_lock_delalloc_range(inode, &tmp, locked_page, &start,
+					 &end, max_bytes);
+	if (!found) {
+		test_msg("Should have found at least one delalloc\n");
+		goto out_bits;
+	}
+	if (start != 0 || end != 4095) {
+		test_msg("Expected start 0 end 4095, got start %Lu end %Lu\n",
+			 start, end);
+		goto out_bits;
+	}
+	unlock_extent(&tmp, start, end);
+	unlock_page(locked_page);
+	page_cache_release(locked_page);
+
+	/*
+	 * Test this scenario
+	 *
+	 * |--- delalloc ---|
+	 *           |--- search ---|
+	 */
+	test_start = 64 * 1024 * 1024;
+	locked_page = find_lock_page(inode->i_mapping,
+				     test_start >> PAGE_CACHE_SHIFT);
+	if (!locked_page) {
+		test_msg("Couldn't find the locked page\n");
+		goto out_bits;
+	}
+	set_extent_delalloc(&tmp, 4096, max_bytes - 1, NULL, GFP_NOFS);
+	start = test_start;
+	end = 0;
+	found = find_lock_delalloc_range(inode, &tmp, locked_page, &start,
+					 &end, max_bytes);
+	if (!found) {
+		test_msg("Couldn't find delalloc in our range\n");
+		goto out_bits;
+	}
+	if (start != test_start || end != max_bytes - 1) {
+		test_msg("Expected start %Lu end %Lu, got start %Lu, end "
+			 "%Lu\n", test_start, max_bytes - 1, start, end);
+		goto out_bits;
+	}
+	if (process_page_range(inode, start, end,
+			       PROCESS_TEST_LOCKED | PROCESS_UNLOCK)) {
+		test_msg("There were unlocked pages in the range\n");
+		goto out_bits;
+	}
+	unlock_extent(&tmp, start, end);
+	/* locked_page was unlocked above */
+	page_cache_release(locked_page);
+
+	/*
+	 * Test this scenario
+	 * |--- delalloc ---|
+	 *                    |--- search ---|
+	 */
+	test_start = max_bytes + 4096;
+	locked_page = find_lock_page(inode->i_mapping, test_start >>
+				     PAGE_CACHE_SHIFT);
+	if (!locked_page) {
+		test_msg("Could'nt find the locked page\n");
+		goto out_bits;
+	}
+	start = test_start;
+	end = 0;
+	found = find_lock_delalloc_range(inode, &tmp, locked_page, &start,
+					 &end, max_bytes);
+	if (found) {
+		test_msg("Found range when we shouldn't have\n");
+		goto out_bits;
+	}
+	if (end != (u64)-1) {
+		test_msg("Did not return the proper end offset\n");
+		goto out_bits;
+	}
+
+	/*
+	 * Test this scenario
+	 * [------- delalloc -------|
+	 * [max_bytes]|-- search--|
+	 *
+	 * We are re-using our test_start from above since it works out well.
+	 */
+	set_extent_delalloc(&tmp, max_bytes, total_dirty - 1, NULL, GFP_NOFS);
+	start = test_start;
+	end = 0;
+	found = find_lock_delalloc_range(inode, &tmp, locked_page, &start,
+					 &end, max_bytes);
+	if (!found) {
+		test_msg("Didn't find our range\n");
+		goto out_bits;
+	}
+	if (start != test_start || end != total_dirty - 1) {
+		test_msg("Expected start %Lu end %Lu, got start %Lu end %Lu\n",
+			 test_start, total_dirty - 1, start, end);
+		goto out_bits;
+	}
+	if (process_page_range(inode, start, end,
+			       PROCESS_TEST_LOCKED | PROCESS_UNLOCK)) {
+		test_msg("Pages in range were not all locked\n");
+		goto out_bits;
+	}
+	unlock_extent(&tmp, start, end);
+
+	/*
+	 * Now to test where we run into a page that is no longer dirty in the
+	 * range we want to find.
+	 */
+	page = find_get_page(inode->i_mapping, (max_bytes + (1 * 1024 * 1024))
+			     >> PAGE_CACHE_SHIFT);
+	if (!page) {
+		test_msg("Couldn't find our page\n");
+		goto out_bits;
+	}
+	ClearPageDirty(page);
+	page_cache_release(page);
+
+	/* We unlocked it in the previous test */
+	lock_page(locked_page);
+	start = test_start;
+	end = 0;
+	/*
+	 * Currently if we fail to find dirty pages in the delalloc range we
+	 * will adjust max_bytes down to PAGE_CACHE_SIZE and then re-search.  If
+	 * this changes at any point in the future we will need to fix this
+	 * tests expected behavior.
+	 */
+	found = find_lock_delalloc_range(inode, &tmp, locked_page, &start,
+					 &end, max_bytes);
+	if (!found) {
+		test_msg("Didn't find our range\n");
+		goto out_bits;
+	}
+	if (start != test_start && end != test_start + PAGE_CACHE_SIZE - 1) {
+		test_msg("Expected start %Lu end %Lu, got start %Lu end %Lu\n",
+			 test_start, test_start + PAGE_CACHE_SIZE - 1, start,
+			 end);
+		goto out_bits;
+	}
+	if (process_page_range(inode, start, end, PROCESS_TEST_LOCKED |
+			       PROCESS_UNLOCK)) {
+		test_msg("Pages in range were not all locked\n");
+		goto out_bits;
+	}
+	ret = 0;
+out_bits:
+	clear_extent_bits(&tmp, 0, total_dirty - 1,
+			  (unsigned long)-1, GFP_NOFS);
+out:
+	if (locked_page)
+		page_cache_release(locked_page);
+	process_page_range(inode, 0, total_dirty - 1,
+			   PROCESS_UNLOCK | PROCESS_RELEASE);
+	iput(inode);
+	return ret;
+}
+
+int btrfs_test_extent_io(void)
+{
+	test_msg("Running find delalloc tests\n");
+	return test_find_delalloc();
+}

fs/btrfs/tests/free-space-tests.c

@@ -0,0 +1,909 @@
+/*
+ * Copyright (C) 2013 Fusion IO.  All rights reserved.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public
+ * License v2 as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public
+ * License along with this program; if not, write to the
+ * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
+ * Boston, MA 021110-1307, USA.
+ */
+
+#include <linux/slab.h>
+#include "btrfs-tests.h"
+#include "../ctree.h"
+#include "../free-space-cache.h"
+
+#define BITS_PER_BITMAP		(PAGE_CACHE_SIZE * 8)
+static struct btrfs_block_group_cache *init_test_block_group(void)
+{
+	struct btrfs_block_group_cache *cache;
+
+	cache = kzalloc(sizeof(*cache), GFP_NOFS);
+	if (!cache)
+		return NULL;
+	cache->free_space_ctl = kzalloc(sizeof(*cache->free_space_ctl),
+					GFP_NOFS);
+	if (!cache->free_space_ctl) {
+		kfree(cache);
+		return NULL;
+	}
+
+	cache->key.objectid = 0;
+	cache->key.offset = 1024 * 1024 * 1024;
+	cache->key.type = BTRFS_BLOCK_GROUP_ITEM_KEY;
+	cache->sectorsize = 4096;
+	cache->full_stripe_len = 4096;
+
+	spin_lock_init(&cache->lock);
+	INIT_LIST_HEAD(&cache->list);
+	INIT_LIST_HEAD(&cache->cluster_list);
+	INIT_LIST_HEAD(&cache->bg_list);
+
+	btrfs_init_free_space_ctl(cache);
+
+	return cache;
+}
+
+/*
+ * This test just does basic sanity checking, making sure we can add an exten
+ * entry and remove space from either end and the middle, and make sure we can
+ * remove space that covers adjacent extent entries.
+ */
+static int test_extents(struct btrfs_block_group_cache *cache)
+{
+	int ret = 0;
+
+	test_msg("Running extent only tests\n");
+
+	/* First just make sure we can remove an entire entry */
+	ret = btrfs_add_free_space(cache, 0, 4 * 1024 * 1024);
+	if (ret) {
+		test_msg("Error adding initial extents %d\n", ret);
+		return ret;
+	}
+
+	ret = btrfs_remove_free_space(cache, 0, 4 * 1024 * 1024);
+	if (ret) {
+		test_msg("Error removing extent %d\n", ret);
+		return ret;
+	}
+
+	if (test_check_exists(cache, 0, 4 * 1024 * 1024)) {
+		test_msg("Full remove left some lingering space\n");
+		return -1;
+	}
+
+	/* Ok edge and middle cases now */
+	ret = btrfs_add_free_space(cache, 0, 4 * 1024 * 1024);
+	if (ret) {
+		test_msg("Error adding half extent %d\n", ret);
+		return ret;
+	}
+
+	ret = btrfs_remove_free_space(cache, 3 * 1024 * 1024, 1 * 1024 * 1024);
+	if (ret) {
+		test_msg("Error removing tail end %d\n", ret);
+		return ret;
+	}
+
+	ret = btrfs_remove_free_space(cache, 0, 1 * 1024 * 1024);
+	if (ret) {
+		test_msg("Error removing front end %d\n", ret);
+		return ret;
+	}
+
+	ret = btrfs_remove_free_space(cache, 2 * 1024 * 1024, 4096);
+	if (ret) {
+		test_msg("Error removing middle piece %d\n", ret);
+		return ret;
+	}
+
+	if (test_check_exists(cache, 0, 1 * 1024 * 1024)) {
+		test_msg("Still have space at the front\n");
+		return -1;
+	}
+
+	if (test_check_exists(cache, 2 * 1024 * 1024, 4096)) {
+		test_msg("Still have space in the middle\n");
+		return -1;
+	}
+
+	if (test_check_exists(cache, 3 * 1024 * 1024, 1 * 1024 * 1024)) {
+		test_msg("Still have space at the end\n");
+		return -1;
+	}
+
+	/* Cleanup */
+	__btrfs_remove_free_space_cache(cache->free_space_ctl);
+
+	return 0;
+}
+
+static int test_bitmaps(struct btrfs_block_group_cache *cache)
+{
+	u64 next_bitmap_offset;
+	int ret;
+
+	test_msg("Running bitmap only tests\n");
+
+	ret = test_add_free_space_entry(cache, 0, 4 * 1024 * 1024, 1);
+	if (ret) {
+		test_msg("Couldn't create a bitmap entry %d\n", ret);
+		return ret;
+	}
+
+	ret = btrfs_remove_free_space(cache, 0, 4 * 1024 * 1024);
+	if (ret) {
+		test_msg("Error removing bitmap full range %d\n", ret);
+		return ret;
+	}
+
+	if (test_check_exists(cache, 0, 4 * 1024 * 1024)) {
+		test_msg("Left some space in bitmap\n");
+		return -1;
+	}
+
+	ret = test_add_free_space_entry(cache, 0, 4 * 1024 * 1024, 1);
+	if (ret) {
+		test_msg("Couldn't add to our bitmap entry %d\n", ret);
+		return ret;
+	}
+
+	ret = btrfs_remove_free_space(cache, 1 * 1024 * 1024, 2 * 1024 * 1024);
+	if (ret) {
+		test_msg("Couldn't remove middle chunk %d\n", ret);
+		return ret;
+	}
+
+	/*
+	 * The first bitmap we have starts at offset 0 so the next one is just
+	 * at the end of the first bitmap.
+	 */
+	next_bitmap_offset = (u64)(BITS_PER_BITMAP * 4096);
+
+	/* Test a bit straddling two bitmaps */
+	ret = test_add_free_space_entry(cache, next_bitmap_offset -
+				   (2 * 1024 * 1024), 4 * 1024 * 1024, 1);
+	if (ret) {
+		test_msg("Couldn't add space that straddles two bitmaps %d\n",
+				ret);
+		return ret;
+	}
+
+	ret = btrfs_remove_free_space(cache, next_bitmap_offset -
+				      (1 * 1024 * 1024), 2 * 1024 * 1024);
+	if (ret) {
+		test_msg("Couldn't remove overlapping space %d\n", ret);
+		return ret;
+	}
+
+	if (test_check_exists(cache, next_bitmap_offset - (1 * 1024 * 1024),
+			 2 * 1024 * 1024)) {
+		test_msg("Left some space when removing overlapping\n");
+		return -1;
+	}
+
+	__btrfs_remove_free_space_cache(cache->free_space_ctl);
+
+	return 0;
+}
+
+/* This is the high grade jackassery */
+static int test_bitmaps_and_extents(struct btrfs_block_group_cache *cache)
+{
+	u64 bitmap_offset = (u64)(BITS_PER_BITMAP * 4096);
+	int ret;
+
+	test_msg("Running bitmap and extent tests\n");
+
+	/*
+	 * First let's do something simple, an extent at the same offset as the
+	 * bitmap, but the free space completely in the extent and then
+	 * completely in the bitmap.
+	 */
+	ret = test_add_free_space_entry(cache, 4 * 1024 * 1024, 1 * 1024 * 1024, 1);
+	if (ret) {
+		test_msg("Couldn't create bitmap entry %d\n", ret);
+		return ret;
+	}
+
+	ret = test_add_free_space_entry(cache, 0, 1 * 1024 * 1024, 0);
+	if (ret) {
+		test_msg("Couldn't add extent entry %d\n", ret);
+		return ret;
+	}
+
+	ret = btrfs_remove_free_space(cache, 0, 1 * 1024 * 1024);
+	if (ret) {
+		test_msg("Couldn't remove extent entry %d\n", ret);
+		return ret;
+	}
+
+	if (test_check_exists(cache, 0, 1 * 1024 * 1024)) {
+		test_msg("Left remnants after our remove\n");
+		return -1;
+	}
+
+	/* Now to add back the extent entry and remove from the bitmap */
+	ret = test_add_free_space_entry(cache, 0, 1 * 1024 * 1024, 0);
+	if (ret) {
+		test_msg("Couldn't re-add extent entry %d\n", ret);
+		return ret;
+	}
+
+	ret = btrfs_remove_free_space(cache, 4 * 1024 * 1024, 1 * 1024 * 1024);
+	if (ret) {
+		test_msg("Couldn't remove from bitmap %d\n", ret);
+		return ret;
+	}
+
+	if (test_check_exists(cache, 4 * 1024 * 1024, 1 * 1024 * 1024)) {
+		test_msg("Left remnants in the bitmap\n");
+		return -1;
+	}
+
+	/*
+	 * Ok so a little more evil, extent entry and bitmap at the same offset,
+	 * removing an overlapping chunk.
+	 */
+	ret = test_add_free_space_entry(cache, 1 * 1024 * 1024, 4 * 1024 * 1024, 1);
+	if (ret) {
+		test_msg("Couldn't add to a bitmap %d\n", ret);
+		return ret;
+	}
+
+	ret = btrfs_remove_free_space(cache, 512 * 1024, 3 * 1024 * 1024);
+	if (ret) {
+		test_msg("Couldn't remove overlapping space %d\n", ret);
+		return ret;
+	}
+
+	if (test_check_exists(cache, 512 * 1024, 3 * 1024 * 1024)) {
+		test_msg("Left over pieces after removing overlapping\n");
+		return -1;
+	}
+
+	__btrfs_remove_free_space_cache(cache->free_space_ctl);
+
+	/* Now with the extent entry offset into the bitmap */
+	ret = test_add_free_space_entry(cache, 4 * 1024 * 1024, 4 * 1024 * 1024, 1);
+	if (ret) {
+		test_msg("Couldn't add space to the bitmap %d\n", ret);
+		return ret;
+	}
+
+	ret = test_add_free_space_entry(cache, 2 * 1024 * 1024, 2 * 1024 * 1024, 0);
+	if (ret) {
+		test_msg("Couldn't add extent to the cache %d\n", ret);
+		return ret;
+	}
+
+	ret = btrfs_remove_free_space(cache, 3 * 1024 * 1024, 4 * 1024 * 1024);
+	if (ret) {
+		test_msg("Problem removing overlapping space %d\n", ret);
+		return ret;
+	}
+
+	if (test_check_exists(cache, 3 * 1024 * 1024, 4 * 1024 * 1024)) {
+		test_msg("Left something behind when removing space");
+		return -1;
+	}
+
+	/*
+	 * This has blown up in the past, the extent entry starts before the
+	 * bitmap entry, but we're trying to remove an offset that falls
+	 * completely within the bitmap range and is in both the extent entry
+	 * and the bitmap entry, looks like this
+	 *
+	 *   [ extent ]
+	 *      [ bitmap ]
+	 *        [ del ]
+	 */
+	__btrfs_remove_free_space_cache(cache->free_space_ctl);
+	ret = test_add_free_space_entry(cache, bitmap_offset + 4 * 1024 * 1024,
+				   4 * 1024 * 1024, 1);
+	if (ret) {
+		test_msg("Couldn't add bitmap %d\n", ret);
+		return ret;
+	}
+
+	ret = test_add_free_space_entry(cache, bitmap_offset - 1 * 1024 * 1024,
+				   5 * 1024 * 1024, 0);
+	if (ret) {
+		test_msg("Couldn't add extent entry %d\n", ret);
+		return ret;
+	}
+
+	ret = btrfs_remove_free_space(cache, bitmap_offset + 1 * 1024 * 1024,
+				      5 * 1024 * 1024);
+	if (ret) {
+		test_msg("Failed to free our space %d\n", ret);
+		return ret;
+	}
+
+	if (test_check_exists(cache, bitmap_offset + 1 * 1024 * 1024,
+			 5 * 1024 * 1024)) {
+		test_msg("Left stuff over\n");
+		return -1;
+	}
+
+	__btrfs_remove_free_space_cache(cache->free_space_ctl);
+
+	/*
+	 * This blew up before, we have part of the free space in a bitmap and
+	 * then the entirety of the rest of the space in an extent.  This used
+	 * to return -EAGAIN back from btrfs_remove_extent, make sure this
+	 * doesn't happen.
+	 */
+	ret = test_add_free_space_entry(cache, 1 * 1024 * 1024, 2 * 1024 * 1024, 1);
+	if (ret) {
+		test_msg("Couldn't add bitmap entry %d\n", ret);
+		return ret;
+	}
+
+	ret = test_add_free_space_entry(cache, 3 * 1024 * 1024, 1 * 1024 * 1024, 0);
+	if (ret) {
+		test_msg("Couldn't add extent entry %d\n", ret);
+		return ret;
+	}
+
+	ret = btrfs_remove_free_space(cache, 1 * 1024 * 1024, 3 * 1024 * 1024);
+	if (ret) {
+		test_msg("Error removing bitmap and extent overlapping %d\n", ret);
+		return ret;
+	}
+
+	__btrfs_remove_free_space_cache(cache->free_space_ctl);
+	return 0;
+}
+
+/* Used by test_steal_space_from_bitmap_to_extent(). */
+static bool test_use_bitmap(struct btrfs_free_space_ctl *ctl,
+			    struct btrfs_free_space *info)
+{
+	return ctl->free_extents > 0;
+}
+
+/* Used by test_steal_space_from_bitmap_to_extent(). */
+static int
+check_num_extents_and_bitmaps(const struct btrfs_block_group_cache *cache,
+			      const int num_extents,
+			      const int num_bitmaps)
+{
+	if (cache->free_space_ctl->free_extents != num_extents) {
+		test_msg("Incorrect # of extent entries in the cache: %d, expected %d\n",
+			 cache->free_space_ctl->free_extents, num_extents);
+		return -EINVAL;
+	}
+	if (cache->free_space_ctl->total_bitmaps != num_bitmaps) {
+		test_msg("Incorrect # of extent entries in the cache: %d, expected %d\n",
+			 cache->free_space_ctl->total_bitmaps, num_bitmaps);
+		return -EINVAL;
+	}
+	return 0;
+}
+
+/* Used by test_steal_space_from_bitmap_to_extent(). */
+static int check_cache_empty(struct btrfs_block_group_cache *cache)
+{
+	u64 offset;
+	u64 max_extent_size;
+
+	/*
+	 * Now lets confirm that there's absolutely no free space left to
+	 * allocate.
+	 */
+	if (cache->free_space_ctl->free_space != 0) {
+		test_msg("Cache free space is not 0\n");
+		return -EINVAL;
+	}
+
+	/* And any allocation request, no matter how small, should fail now. */
+	offset = btrfs_find_space_for_alloc(cache, 0, 4096, 0,
+					    &max_extent_size);
+	if (offset != 0) {
+		test_msg("Space allocation did not fail, returned offset: %llu",
+			 offset);
+		return -EINVAL;
+	}
+
+	/* And no extent nor bitmap entries in the cache anymore. */
+	return check_num_extents_and_bitmaps(cache, 0, 0);
+}
+
+/*
+ * Before we were able to steal free space from a bitmap entry to an extent
+ * entry, we could end up with 2 entries representing a contiguous free space.
+ * One would be an extent entry and the other a bitmap entry. Since in order
+ * to allocate space to a caller we use only 1 entry, we couldn't return that
+ * whole range to the caller if it was requested. This forced the caller to
+ * either assume ENOSPC or perform several smaller space allocations, which
+ * wasn't optimal as they could be spread all over the block group while under
+ * concurrency (extra overhead and fragmentation).
+ *
+ * This stealing approach is benefical, since we always prefer to allocate from
+ * extent entries, both for clustered and non-clustered allocation requests.
+ */
+static int
+test_steal_space_from_bitmap_to_extent(struct btrfs_block_group_cache *cache)
+{
+	int ret;
+	u64 offset;
+	u64 max_extent_size;
+
+	bool (*use_bitmap_op)(struct btrfs_free_space_ctl *,
+			      struct btrfs_free_space *);
+
+	test_msg("Running space stealing from bitmap to extent\n");
+
+	/*
+	 * For this test, we want to ensure we end up with an extent entry
+	 * immediately adjacent to a bitmap entry, where the bitmap starts
+	 * at an offset where the extent entry ends. We keep adding and
+	 * removing free space to reach into this state, but to get there
+	 * we need to reach a point where marking new free space doesn't
+	 * result in adding new extent entries or merging the new space
+	 * with existing extent entries - the space ends up being marked
+	 * in an existing bitmap that covers the new free space range.
+	 *
+	 * To get there, we need to reach the threshold defined set at
+	 * cache->free_space_ctl->extents_thresh, which currently is
+	 * 256 extents on a x86_64 system at least, and a few other
+	 * conditions (check free_space_cache.c). Instead of making the
+	 * test much longer and complicated, use a "use_bitmap" operation
+	 * that forces use of bitmaps as soon as we have at least 1
+	 * extent entry.
+	 */
+	use_bitmap_op = cache->free_space_ctl->op->use_bitmap;
+	cache->free_space_ctl->op->use_bitmap = test_use_bitmap;
+
+	/*
+	 * Extent entry covering free space range [128Mb - 256Kb, 128Mb - 128Kb[
+	 */
+	ret = test_add_free_space_entry(cache, 128 * 1024 * 1024 - 256 * 1024,
+					128 * 1024, 0);
+	if (ret) {
+		test_msg("Couldn't add extent entry %d\n", ret);
+		return ret;
+	}
+
+	/* Bitmap entry covering free space range [128Mb + 512Kb, 256Mb[ */
+	ret = test_add_free_space_entry(cache, 128 * 1024 * 1024 + 512 * 1024,
+					128 * 1024 * 1024 - 512 * 1024, 1);
+	if (ret) {
+		test_msg("Couldn't add bitmap entry %d\n", ret);
+		return ret;
+	}
+
+	ret = check_num_extents_and_bitmaps(cache, 2, 1);
+	if (ret)
+		return ret;
+
+	/*
+	 * Now make only the first 256Kb of the bitmap marked as free, so that
+	 * we end up with only the following ranges marked as free space:
+	 *
+	 * [128Mb - 256Kb, 128Mb - 128Kb[
+	 * [128Mb + 512Kb, 128Mb + 768Kb[
+	 */
+	ret = btrfs_remove_free_space(cache,
+				      128 * 1024 * 1024 + 768 * 1024,
+				      128 * 1024 * 1024 - 768 * 1024);
+	if (ret) {
+		test_msg("Failed to free part of bitmap space %d\n", ret);
+		return ret;
+	}
+
+	/* Confirm that only those 2 ranges are marked as free. */
+	if (!test_check_exists(cache, 128 * 1024 * 1024 - 256 * 1024,
+			       128 * 1024)) {
+		test_msg("Free space range missing\n");
+		return -ENOENT;
+	}
+	if (!test_check_exists(cache, 128 * 1024 * 1024 + 512 * 1024,
+			       256 * 1024)) {
+		test_msg("Free space range missing\n");
+		return -ENOENT;
+	}
+
+	/*
+	 * Confirm that the bitmap range [128Mb + 768Kb, 256Mb[ isn't marked
+	 * as free anymore.
+	 */
+	if (test_check_exists(cache, 128 * 1024 * 1024 + 768 * 1024,
+			      128 * 1024 * 1024 - 768 * 1024)) {
+		test_msg("Bitmap region not removed from space cache\n");
+		return -EINVAL;
+	}
+
+	/*
+	 * Confirm that the region [128Mb + 256Kb, 128Mb + 512Kb[, which is
+	 * covered by the bitmap, isn't marked as free.
+	 */
+	if (test_check_exists(cache, 128 * 1024 * 1024 + 256 * 1024,
+			      256 * 1024)) {
+		test_msg("Invalid bitmap region marked as free\n");
+		return -EINVAL;
+	}
+
+	/*
+	 * Confirm that the region [128Mb, 128Mb + 256Kb[, which is covered
+	 * by the bitmap too, isn't marked as free either.
+	 */
+	if (test_check_exists(cache, 128 * 1024 * 1024,
+			      256 * 1024)) {
+		test_msg("Invalid bitmap region marked as free\n");
+		return -EINVAL;
+	}
+
+	/*
+	 * Now lets mark the region [128Mb, 128Mb + 512Kb[ as free too. But,
+	 * lets make sure the free space cache marks it as free in the bitmap,
+	 * and doesn't insert a new extent entry to represent this region.
+	 */
+	ret = btrfs_add_free_space(cache, 128 * 1024 * 1024, 512 * 1024);
+	if (ret) {
+		test_msg("Error adding free space: %d\n", ret);
+		return ret;
+	}
+	/* Confirm the region is marked as free. */
+	if (!test_check_exists(cache, 128 * 1024 * 1024, 512 * 1024)) {
+		test_msg("Bitmap region not marked as free\n");
+		return -ENOENT;
+	}
+
+	/*
+	 * Confirm that no new extent entries or bitmap entries were added to
+	 * the cache after adding that free space region.
+	 */
+	ret = check_num_extents_and_bitmaps(cache, 2, 1);
+	if (ret)
+		return ret;
+
+	/*
+	 * Now lets add a small free space region to the right of the previous
+	 * one, which is not contiguous with it and is part of the bitmap too.
+	 * The goal is to test that the bitmap entry space stealing doesn't
+	 * steal this space region.
+	 */
+	ret = btrfs_add_free_space(cache, 128 * 1024 * 1024 + 16 * 1024 * 1024,
+				   4096);
+	if (ret) {
+		test_msg("Error adding free space: %d\n", ret);
+		return ret;
+	}
+
+	/*
+	 * Confirm that no new extent entries or bitmap entries were added to
+	 * the cache after adding that free space region.
+	 */
+	ret = check_num_extents_and_bitmaps(cache, 2, 1);
+	if (ret)
+		return ret;
+
+	/*
+	 * Now mark the region [128Mb - 128Kb, 128Mb[ as free too. This will
+	 * expand the range covered by the existing extent entry that represents
+	 * the free space [128Mb - 256Kb, 128Mb - 128Kb[.
+	 */
+	ret = btrfs_add_free_space(cache, 128 * 1024 * 1024 - 128 * 1024,
+				   128 * 1024);
+	if (ret) {
+		test_msg("Error adding free space: %d\n", ret);
+		return ret;
+	}
+	/* Confirm the region is marked as free. */
+	if (!test_check_exists(cache, 128 * 1024 * 1024 - 128 * 1024,
+			       128 * 1024)) {
+		test_msg("Extent region not marked as free\n");
+		return -ENOENT;
+	}
+
+	/*
+	 * Confirm that our extent entry didn't stole all free space from the
+	 * bitmap, because of the small 4Kb free space region.
+	 */
+	ret = check_num_extents_and_bitmaps(cache, 2, 1);
+	if (ret)
+		return ret;
+
+	/*
+	 * So now we have the range [128Mb - 256Kb, 128Mb + 768Kb[ as free
+	 * space. Without stealing bitmap free space into extent entry space,
+	 * we would have all this free space represented by 2 entries in the
+	 * cache:
+	 *
+	 * extent entry covering range: [128Mb - 256Kb, 128Mb[
+	 * bitmap entry covering range: [128Mb, 128Mb + 768Kb[
+	 *
+	 * Attempting to allocate the whole free space (1Mb) would fail, because
+	 * we can't allocate from multiple entries.
+	 * With the bitmap free space stealing, we get a single extent entry
+	 * that represents the 1Mb free space, and therefore we're able to
+	 * allocate the whole free space at once.
+	 */
+	if (!test_check_exists(cache, 128 * 1024 * 1024 - 256 * 1024,
+			       1 * 1024 * 1024)) {
+		test_msg("Expected region not marked as free\n");
+		return -ENOENT;
+	}
+
+	if (cache->free_space_ctl->free_space != (1 * 1024 * 1024 + 4096)) {
+		test_msg("Cache free space is not 1Mb + 4Kb\n");
+		return -EINVAL;
+	}
+
+	offset = btrfs_find_space_for_alloc(cache,
+					    0, 1 * 1024 * 1024, 0,
+					    &max_extent_size);
+	if (offset != (128 * 1024 * 1024 - 256 * 1024)) {
+		test_msg("Failed to allocate 1Mb from space cache, returned offset is: %llu\n",
+			 offset);
+		return -EINVAL;
+	}
+
+	/* All that remains is a 4Kb free space region in a bitmap. Confirm. */
+	ret = check_num_extents_and_bitmaps(cache, 1, 1);
+	if (ret)
+		return ret;
+
+	if (cache->free_space_ctl->free_space != 4096) {
+		test_msg("Cache free space is not 4Kb\n");
+		return -EINVAL;
+	}
+
+	offset = btrfs_find_space_for_alloc(cache,
+					    0, 4096, 0,
+					    &max_extent_size);
+	if (offset != (128 * 1024 * 1024 + 16 * 1024 * 1024)) {
+		test_msg("Failed to allocate 4Kb from space cache, returned offset is: %llu\n",
+			 offset);
+		return -EINVAL;
+	}
+
+	ret = check_cache_empty(cache);
+	if (ret)
+		return ret;
+
+	__btrfs_remove_free_space_cache(cache->free_space_ctl);
+
+	/*
+	 * Now test a similar scenario, but where our extent entry is located
+	 * to the right of the bitmap entry, so that we can check that stealing
+	 * space from a bitmap to the front of an extent entry works.
+	 */
+
+	/*
+	 * Extent entry covering free space range [128Mb + 128Kb, 128Mb + 256Kb[
+	 */
+	ret = test_add_free_space_entry(cache, 128 * 1024 * 1024 + 128 * 1024,
+					128 * 1024, 0);
+	if (ret) {
+		test_msg("Couldn't add extent entry %d\n", ret);
+		return ret;
+	}
+
+	/* Bitmap entry covering free space range [0, 128Mb - 512Kb[ */
+	ret = test_add_free_space_entry(cache, 0,
+					128 * 1024 * 1024 - 512 * 1024, 1);
+	if (ret) {
+		test_msg("Couldn't add bitmap entry %d\n", ret);
+		return ret;
+	}
+
+	ret = check_num_extents_and_bitmaps(cache, 2, 1);
+	if (ret)
+		return ret;
+
+	/*
+	 * Now make only the last 256Kb of the bitmap marked as free, so that
+	 * we end up with only the following ranges marked as free space:
+	 *
+	 * [128Mb + 128b, 128Mb + 256Kb[
+	 * [128Mb - 768Kb, 128Mb - 512Kb[
+	 */
+	ret = btrfs_remove_free_space(cache,
+				      0,
+				      128 * 1024 * 1024 - 768 * 1024);
+	if (ret) {
+		test_msg("Failed to free part of bitmap space %d\n", ret);
+		return ret;
+	}
+
+	/* Confirm that only those 2 ranges are marked as free. */
+	if (!test_check_exists(cache, 128 * 1024 * 1024 + 128 * 1024,
+			       128 * 1024)) {
+		test_msg("Free space range missing\n");
+		return -ENOENT;
+	}
+	if (!test_check_exists(cache, 128 * 1024 * 1024 - 768 * 1024,
+			       256 * 1024)) {
+		test_msg("Free space range missing\n");
+		return -ENOENT;
+	}
+
+	/*
+	 * Confirm that the bitmap range [0, 128Mb - 768Kb[ isn't marked
+	 * as free anymore.
+	 */
+	if (test_check_exists(cache, 0,
+			      128 * 1024 * 1024 - 768 * 1024)) {
+		test_msg("Bitmap region not removed from space cache\n");
+		return -EINVAL;
+	}
+
+	/*
+	 * Confirm that the region [128Mb - 512Kb, 128Mb[, which is
+	 * covered by the bitmap, isn't marked as free.
+	 */
+	if (test_check_exists(cache, 128 * 1024 * 1024 - 512 * 1024,
+			      512 * 1024)) {
+		test_msg("Invalid bitmap region marked as free\n");
+		return -EINVAL;
+	}
+
+	/*
+	 * Now lets mark the region [128Mb - 512Kb, 128Mb[ as free too. But,
+	 * lets make sure the free space cache marks it as free in the bitmap,
+	 * and doesn't insert a new extent entry to represent this region.
+	 */
+	ret = btrfs_add_free_space(cache, 128 * 1024 * 1024 - 512 * 1024,
+				   512 * 1024);
+	if (ret) {
+		test_msg("Error adding free space: %d\n", ret);
+		return ret;
+	}
+	/* Confirm the region is marked as free. */
+	if (!test_check_exists(cache, 128 * 1024 * 1024 - 512 * 1024,
+			       512 * 1024)) {
+		test_msg("Bitmap region not marked as free\n");
+		return -ENOENT;
+	}
+
+	/*
+	 * Confirm that no new extent entries or bitmap entries were added to
+	 * the cache after adding that free space region.
+	 */
+	ret = check_num_extents_and_bitmaps(cache, 2, 1);
+	if (ret)
+		return ret;
+
+	/*
+	 * Now lets add a small free space region to the left of the previous
+	 * one, which is not contiguous with it and is part of the bitmap too.
+	 * The goal is to test that the bitmap entry space stealing doesn't
+	 * steal this space region.
+	 */
+	ret = btrfs_add_free_space(cache, 32 * 1024 * 1024, 8192);
+	if (ret) {
+		test_msg("Error adding free space: %d\n", ret);
+		return ret;
+	}
+
+	/*
+	 * Now mark the region [128Mb, 128Mb + 128Kb[ as free too. This will
+	 * expand the range covered by the existing extent entry that represents
+	 * the free space [128Mb + 128Kb, 128Mb + 256Kb[.
+	 */
+	ret = btrfs_add_free_space(cache, 128 * 1024 * 1024, 128 * 1024);
+	if (ret) {
+		test_msg("Error adding free space: %d\n", ret);
+		return ret;
+	}
+	/* Confirm the region is marked as free. */
+	if (!test_check_exists(cache, 128 * 1024 * 1024, 128 * 1024)) {
+		test_msg("Extent region not marked as free\n");
+		return -ENOENT;
+	}
+
+	/*
+	 * Confirm that our extent entry didn't stole all free space from the
+	 * bitmap, because of the small 8Kb free space region.
+	 */
+	ret = check_num_extents_and_bitmaps(cache, 2, 1);
+	if (ret)
+		return ret;
+
+	/*
+	 * So now we have the range [128Mb - 768Kb, 128Mb + 256Kb[ as free
+	 * space. Without stealing bitmap free space into extent entry space,
+	 * we would have all this free space represented by 2 entries in the
+	 * cache:
+	 *
+	 * extent entry covering range: [128Mb, 128Mb + 256Kb[
+	 * bitmap entry covering range: [128Mb - 768Kb, 128Mb[
+	 *
+	 * Attempting to allocate the whole free space (1Mb) would fail, because
+	 * we can't allocate from multiple entries.
+	 * With the bitmap free space stealing, we get a single extent entry
+	 * that represents the 1Mb free space, and therefore we're able to
+	 * allocate the whole free space at once.
+	 */
+	if (!test_check_exists(cache, 128 * 1024 * 1024 - 768 * 1024,
+			       1 * 1024 * 1024)) {
+		test_msg("Expected region not marked as free\n");
+		return -ENOENT;
+	}
+
+	if (cache->free_space_ctl->free_space != (1 * 1024 * 1024 + 8192)) {
+		test_msg("Cache free space is not 1Mb + 8Kb\n");
+		return -EINVAL;
+	}
+
+	offset = btrfs_find_space_for_alloc(cache,
+					    0, 1 * 1024 * 1024, 0,
+					    &max_extent_size);
+	if (offset != (128 * 1024 * 1024 - 768 * 1024)) {
+		test_msg("Failed to allocate 1Mb from space cache, returned offset is: %llu\n",
+			 offset);
+		return -EINVAL;
+	}
+
+	/* All that remains is a 8Kb free space region in a bitmap. Confirm. */
+	ret = check_num_extents_and_bitmaps(cache, 1, 1);
+	if (ret)
+		return ret;
+
+	if (cache->free_space_ctl->free_space != 8192) {
+		test_msg("Cache free space is not 8Kb\n");
+		return -EINVAL;
+	}
+
+	offset = btrfs_find_space_for_alloc(cache,
+					    0, 8192, 0,
+					    &max_extent_size);
+	if (offset != (32 * 1024 * 1024)) {
+		test_msg("Failed to allocate 8Kb from space cache, returned offset is: %llu\n",
+			 offset);
+		return -EINVAL;
+	}
+
+	ret = check_cache_empty(cache);
+	if (ret)
+		return ret;
+
+	cache->free_space_ctl->op->use_bitmap = use_bitmap_op;
+	__btrfs_remove_free_space_cache(cache->free_space_ctl);
+
+	return 0;
+}
+
+int btrfs_test_free_space_cache(void)
+{
+	struct btrfs_block_group_cache *cache;
+	int ret;
+
+	test_msg("Running btrfs free space cache tests\n");
+
+	cache = init_test_block_group();
+	if (!cache) {
+		test_msg("Couldn't run the tests\n");
+		return 0;
+	}
+
+	ret = test_extents(cache);
+	if (ret)
+		goto out;
+	ret = test_bitmaps(cache);
+	if (ret)
+		goto out;
+	ret = test_bitmaps_and_extents(cache);
+	if (ret)
+		goto out;
+
+	ret = test_steal_space_from_bitmap_to_extent(cache);
+out:
+	__btrfs_remove_free_space_cache(cache->free_space_ctl);
+	kfree(cache->free_space_ctl);
+	kfree(cache);
+	test_msg("Free space cache tests finished\n");
+	return ret;
+}

fs/btrfs/tests/inode-tests.c

@@ -0,0 +1,928 @@
+/*
+ * Copyright (C) 2013 Fusion IO.  All rights reserved.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public
+ * License v2 as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public
+ * License along with this program; if not, write to the
+ * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
+ * Boston, MA 021110-1307, USA.
+ */
+
+#include "btrfs-tests.h"
+#include "../ctree.h"
+#include "../btrfs_inode.h"
+#include "../disk-io.h"
+#include "../extent_io.h"
+#include "../volumes.h"
+
+static void insert_extent(struct btrfs_root *root, u64 start, u64 len,
+			  u64 ram_bytes, u64 offset, u64 disk_bytenr,
+			  u64 disk_len, u32 type, u8 compression, int slot)
+{
+	struct btrfs_path path;
+	struct btrfs_file_extent_item *fi;
+	struct extent_buffer *leaf = root->node;
+	struct btrfs_key key;
+	u32 value_len = sizeof(struct btrfs_file_extent_item);
+
+	if (type == BTRFS_FILE_EXTENT_INLINE)
+		value_len += len;
+	memset(&path, 0, sizeof(path));
+
+	path.nodes[0] = leaf;
+	path.slots[0] = slot;
+
+	key.objectid = BTRFS_FIRST_FREE_OBJECTID;
+	key.type = BTRFS_EXTENT_DATA_KEY;
+	key.offset = start;
+
+	setup_items_for_insert(root, &path, &key, &value_len, value_len,
+			       value_len + sizeof(struct btrfs_item), 1);
+	fi = btrfs_item_ptr(leaf, slot, struct btrfs_file_extent_item);
+	btrfs_set_file_extent_generation(leaf, fi, 1);
+	btrfs_set_file_extent_type(leaf, fi, type);
+	btrfs_set_file_extent_disk_bytenr(leaf, fi, disk_bytenr);
+	btrfs_set_file_extent_disk_num_bytes(leaf, fi, disk_len);
+	btrfs_set_file_extent_offset(leaf, fi, offset);
+	btrfs_set_file_extent_num_bytes(leaf, fi, len);
+	btrfs_set_file_extent_ram_bytes(leaf, fi, ram_bytes);
+	btrfs_set_file_extent_compression(leaf, fi, compression);
+	btrfs_set_file_extent_encryption(leaf, fi, 0);
+	btrfs_set_file_extent_other_encoding(leaf, fi, 0);
+}
+
+static void insert_inode_item_key(struct btrfs_root *root)
+{
+	struct btrfs_path path;
+	struct extent_buffer *leaf = root->node;
+	struct btrfs_key key;
+	u32 value_len = 0;
+
+	memset(&path, 0, sizeof(path));
+
+	path.nodes[0] = leaf;
+	path.slots[0] = 0;
+
+	key.objectid = BTRFS_INODE_ITEM_KEY;
+	key.type = BTRFS_INODE_ITEM_KEY;
+	key.offset = 0;
+
+	setup_items_for_insert(root, &path, &key, &value_len, value_len,
+			       value_len + sizeof(struct btrfs_item), 1);
+}
+
+/*
+ * Build the most complicated map of extents the earth has ever seen.  We want
+ * this so we can test all of the corner cases of btrfs_get_extent.  Here is a
+ * diagram of how the extents will look though this may not be possible we still
+ * want to make sure everything acts normally (the last number is not inclusive)
+ *
+ * [0 - 5][5 -  6][6 - 10][10 - 4096][  4096 - 8192 ][8192 - 12288]
+ * [hole ][inline][ hole ][ regular ][regular1 split][    hole    ]
+ *
+ * [ 12288 - 20480][20480 - 24576][  24576 - 28672  ][28672 - 36864][36864 - 45056]
+ * [regular1 split][   prealloc1 ][prealloc1 written][   prealloc1 ][ compressed  ]
+ *
+ * [45056 - 49152][49152-53248][53248-61440][61440-65536][     65536+81920   ]
+ * [ compressed1 ][  regular  ][compressed1][  regular  ][ hole but no extent]
+ *
+ * [81920-86016]
+ * [  regular  ]
+ */
+static void setup_file_extents(struct btrfs_root *root)
+{
+	int slot = 0;
+	u64 disk_bytenr = 1 * 1024 * 1024;
+	u64 offset = 0;
+
+	/* First we want a hole */
+	insert_extent(root, offset, 5, 5, 0, 0, 0, BTRFS_FILE_EXTENT_REG, 0,
+		      slot);
+	slot++;
+	offset += 5;
+
+	/*
+	 * Now we want an inline extent, I don't think this is possible but hey
+	 * why not?  Also keep in mind if we have an inline extent it counts as
+	 * the whole first page.  If we were to expand it we would have to cow
+	 * and we wouldn't have an inline extent anymore.
+	 */
+	insert_extent(root, offset, 1, 1, 0, 0, 0, BTRFS_FILE_EXTENT_INLINE, 0,
+		      slot);
+	slot++;
+	offset = 4096;
+
+	/* Now another hole */
+	insert_extent(root, offset, 4, 4, 0, 0, 0, BTRFS_FILE_EXTENT_REG, 0,
+		      slot);
+	slot++;
+	offset += 4;
+
+	/* Now for a regular extent */
+	insert_extent(root, offset, 4095, 4095, 0, disk_bytenr, 4096,
+		      BTRFS_FILE_EXTENT_REG, 0, slot);
+	slot++;
+	disk_bytenr += 4096;
+	offset += 4095;
+
+	/*
+	 * Now for 3 extents that were split from a hole punch so we test
+	 * offsets properly.
+	 */
+	insert_extent(root, offset, 4096, 16384, 0, disk_bytenr, 16384,
+		      BTRFS_FILE_EXTENT_REG, 0, slot);
+	slot++;
+	offset += 4096;
+	insert_extent(root, offset, 4096, 4096, 0, 0, 0, BTRFS_FILE_EXTENT_REG,
+		      0, slot);
+	slot++;
+	offset += 4096;
+	insert_extent(root, offset, 8192, 16384, 8192, disk_bytenr, 16384,
+		      BTRFS_FILE_EXTENT_REG, 0, slot);
+	slot++;
+	offset += 8192;
+	disk_bytenr += 16384;
+
+	/* Now for a unwritten prealloc extent */
+	insert_extent(root, offset, 4096, 4096, 0, disk_bytenr, 4096,
+		      BTRFS_FILE_EXTENT_PREALLOC, 0, slot);
+	slot++;
+	offset += 4096;
+
+	/*
+	 * We want to jack up disk_bytenr a little more so the em stuff doesn't
+	 * merge our records.
+	 */
+	disk_bytenr += 8192;
+
+	/*
+	 * Now for a partially written prealloc extent, basically the same as
+	 * the hole punch example above.  Ram_bytes never changes when you mark
+	 * extents written btw.
+	 */
+	insert_extent(root, offset, 4096, 16384, 0, disk_bytenr, 16384,
+		      BTRFS_FILE_EXTENT_PREALLOC, 0, slot);
+	slot++;
+	offset += 4096;
+	insert_extent(root, offset, 4096, 16384, 4096, disk_bytenr, 16384,
+		      BTRFS_FILE_EXTENT_REG, 0, slot);
+	slot++;
+	offset += 4096;
+	insert_extent(root, offset, 8192, 16384, 8192, disk_bytenr, 16384,
+		      BTRFS_FILE_EXTENT_PREALLOC, 0, slot);
+	slot++;
+	offset += 8192;
+	disk_bytenr += 16384;
+
+	/* Now a normal compressed extent */
+	insert_extent(root, offset, 8192, 8192, 0, disk_bytenr, 4096,
+		      BTRFS_FILE_EXTENT_REG, BTRFS_COMPRESS_ZLIB, slot);
+	slot++;
+	offset += 8192;
+	/* No merges */
+	disk_bytenr += 8192;
+
+	/* Now a split compressed extent */
+	insert_extent(root, offset, 4096, 16384, 0, disk_bytenr, 4096,
+		      BTRFS_FILE_EXTENT_REG, BTRFS_COMPRESS_ZLIB, slot);
+	slot++;
+	offset += 4096;
+	insert_extent(root, offset, 4096, 4096, 0, disk_bytenr + 4096, 4096,
+		      BTRFS_FILE_EXTENT_REG, 0, slot);
+	slot++;
+	offset += 4096;
+	insert_extent(root, offset, 8192, 16384, 8192, disk_bytenr, 4096,
+		      BTRFS_FILE_EXTENT_REG, BTRFS_COMPRESS_ZLIB, slot);
+	slot++;
+	offset += 8192;
+	disk_bytenr += 8192;
+
+	/* Now extents that have a hole but no hole extent */
+	insert_extent(root, offset, 4096, 4096, 0, disk_bytenr, 4096,
+		      BTRFS_FILE_EXTENT_REG, 0, slot);
+	slot++;
+	offset += 16384;
+	disk_bytenr += 4096;
+	insert_extent(root, offset, 4096, 4096, 0, disk_bytenr, 4096,
+		      BTRFS_FILE_EXTENT_REG, 0, slot);
+}
+
+static unsigned long prealloc_only = 0;
+static unsigned long compressed_only = 0;
+static unsigned long vacancy_only = 0;
+
+static noinline int test_btrfs_get_extent(void)
+{
+	struct inode *inode = NULL;
+	struct btrfs_root *root = NULL;
+	struct extent_map *em = NULL;
+	u64 orig_start;
+	u64 disk_bytenr;
+	u64 offset;
+	int ret = -ENOMEM;
+
+	inode = btrfs_new_test_inode();
+	if (!inode) {
+		test_msg("Couldn't allocate inode\n");
+		return ret;
+	}
+
+	BTRFS_I(inode)->location.type = BTRFS_INODE_ITEM_KEY;
+	BTRFS_I(inode)->location.objectid = BTRFS_FIRST_FREE_OBJECTID;
+	BTRFS_I(inode)->location.offset = 0;
+
+	root = btrfs_alloc_dummy_root();
+	if (IS_ERR(root)) {
+		test_msg("Couldn't allocate root\n");
+		goto out;
+	}
+
+	/*
+	 * We do this since btrfs_get_extent wants to assign em->bdev to
+	 * root->fs_info->fs_devices->latest_bdev.
+	 */
+	root->fs_info = btrfs_alloc_dummy_fs_info();
+	if (!root->fs_info) {
+		test_msg("Couldn't allocate dummy fs info\n");
+		goto out;
+	}
+
+	root->node = alloc_dummy_extent_buffer(0, 4096);
+	if (!root->node) {
+		test_msg("Couldn't allocate dummy buffer\n");
+		goto out;
+	}
+
+	/*
+	 * We will just free a dummy node if it's ref count is 2 so we need an
+	 * extra ref so our searches don't accidently release our page.
+	 */
+	extent_buffer_get(root->node);
+	btrfs_set_header_nritems(root->node, 0);
+	btrfs_set_header_level(root->node, 0);
+	ret = -EINVAL;
+
+	/* First with no extents */
+	BTRFS_I(inode)->root = root;
+	em = btrfs_get_extent(inode, NULL, 0, 0, 4096, 0);
+	if (IS_ERR(em)) {
+		em = NULL;
+		test_msg("Got an error when we shouldn't have\n");
+		goto out;
+	}
+	if (em->block_start != EXTENT_MAP_HOLE) {
+		test_msg("Expected a hole, got %llu\n", em->block_start);
+		goto out;
+	}
+	if (!test_bit(EXTENT_FLAG_VACANCY, &em->flags)) {
+		test_msg("Vacancy flag wasn't set properly\n");
+		goto out;
+	}
+	free_extent_map(em);
+	btrfs_drop_extent_cache(inode, 0, (u64)-1, 0);
+
+	/*
+	 * All of the magic numbers are based on the mapping setup in
+	 * setup_file_extents, so if you change anything there you need to
+	 * update the comment and update the expected values below.
+	 */
+	setup_file_extents(root);
+
+	em = btrfs_get_extent(inode, NULL, 0, 0, (u64)-1, 0);
+	if (IS_ERR(em)) {
+		test_msg("Got an error when we shouldn't have\n");
+		goto out;
+	}
+	if (em->block_start != EXTENT_MAP_HOLE) {
+		test_msg("Expected a hole, got %llu\n", em->block_start);
+		goto out;
+	}
+	if (em->start != 0 || em->len != 5) {
+		test_msg("Unexpected extent wanted start 0 len 5, got start "
+			 "%llu len %llu\n", em->start, em->len);
+		goto out;
+	}
+	if (em->flags != 0) {
+		test_msg("Unexpected flags set, want 0 have %lu\n", em->flags);
+		goto out;
+	}
+	offset = em->start + em->len;
+	free_extent_map(em);
+
+	em = btrfs_get_extent(inode, NULL, 0, offset, 4096, 0);
+	if (IS_ERR(em)) {
+		test_msg("Got an error when we shouldn't have\n");
+		goto out;
+	}
+	if (em->block_start != EXTENT_MAP_INLINE) {
+		test_msg("Expected an inline, got %llu\n", em->block_start);
+		goto out;
+	}
+	if (em->start != offset || em->len != 4091) {
+		test_msg("Unexpected extent wanted start %llu len 1, got start "
+			 "%llu len %llu\n", offset, em->start, em->len);
+		goto out;
+	}
+	if (em->flags != 0) {
+		test_msg("Unexpected flags set, want 0 have %lu\n", em->flags);
+		goto out;
+	}
+	/*
+	 * We don't test anything else for inline since it doesn't get set
+	 * unless we have a page for it to write into.  Maybe we should change
+	 * this?
+	 */
+	offset = em->start + em->len;
+	free_extent_map(em);
+
+	em = btrfs_get_extent(inode, NULL, 0, offset, 4096, 0);
+	if (IS_ERR(em)) {
+		test_msg("Got an error when we shouldn't have\n");
+		goto out;
+	}
+	if (em->block_start != EXTENT_MAP_HOLE) {
+		test_msg("Expected a hole, got %llu\n", em->block_start);
+		goto out;
+	}
+	if (em->start != offset || em->len != 4) {
+		test_msg("Unexpected extent wanted start %llu len 4, got start "
+			 "%llu len %llu\n", offset, em->start, em->len);
+		goto out;
+	}
+	if (em->flags != 0) {
+		test_msg("Unexpected flags set, want 0 have %lu\n", em->flags);
+		goto out;
+	}
+	offset = em->start + em->len;
+	free_extent_map(em);
+
+	/* Regular extent */
+	em = btrfs_get_extent(inode, NULL, 0, offset, 4096, 0);
+	if (IS_ERR(em)) {
+		test_msg("Got an error when we shouldn't have\n");
+		goto out;
+	}
+	if (em->block_start >= EXTENT_MAP_LAST_BYTE) {
+		test_msg("Expected a real extent, got %llu\n", em->block_start);
+		goto out;
+	}
+	if (em->start != offset || em->len != 4095) {
+		test_msg("Unexpected extent wanted start %llu len 4095, got "
+			 "start %llu len %llu\n", offset, em->start, em->len);
+		goto out;
+	}
+	if (em->flags != 0) {
+		test_msg("Unexpected flags set, want 0 have %lu\n", em->flags);
+		goto out;
+	}
+	if (em->orig_start != em->start) {
+		test_msg("Wrong orig offset, want %llu, have %llu\n", em->start,
+			 em->orig_start);
+		goto out;
+	}
+	offset = em->start + em->len;
+	free_extent_map(em);
+
+	/* The next 3 are split extents */
+	em = btrfs_get_extent(inode, NULL, 0, offset, 4096, 0);
+	if (IS_ERR(em)) {
+		test_msg("Got an error when we shouldn't have\n");
+		goto out;
+	}
+	if (em->block_start >= EXTENT_MAP_LAST_BYTE) {
+		test_msg("Expected a real extent, got %llu\n", em->block_start);
+		goto out;
+	}
+	if (em->start != offset || em->len != 4096) {
+		test_msg("Unexpected extent wanted start %llu len 4096, got "
+			 "start %llu len %llu\n", offset, em->start, em->len);
+		goto out;
+	}
+	if (em->flags != 0) {
+		test_msg("Unexpected flags set, want 0 have %lu\n", em->flags);
+		goto out;
+	}
+	if (em->orig_start != em->start) {
+		test_msg("Wrong orig offset, want %llu, have %llu\n", em->start,
+			 em->orig_start);
+		goto out;
+	}
+	disk_bytenr = em->block_start;
+	orig_start = em->start;
+	offset = em->start + em->len;
+	free_extent_map(em);
+
+	em = btrfs_get_extent(inode, NULL, 0, offset, 4096, 0);
+	if (IS_ERR(em)) {
+		test_msg("Got an error when we shouldn't have\n");
+		goto out;
+	}
+	if (em->block_start != EXTENT_MAP_HOLE) {
+		test_msg("Expected a hole, got %llu\n", em->block_start);
+		goto out;
+	}
+	if (em->start != offset || em->len != 4096) {
+		test_msg("Unexpected extent wanted start %llu len 4096, got "
+			 "start %llu len %llu\n", offset, em->start, em->len);
+		goto out;
+	}
+	if (em->flags != 0) {
+		test_msg("Unexpected flags set, want 0 have %lu\n", em->flags);
+		goto out;
+	}
+	offset = em->start + em->len;
+	free_extent_map(em);
+
+	em = btrfs_get_extent(inode, NULL, 0, offset, 4096, 0);
+	if (IS_ERR(em)) {
+		test_msg("Got an error when we shouldn't have\n");
+		goto out;
+	}
+	if (em->block_start >= EXTENT_MAP_LAST_BYTE) {
+		test_msg("Expected a real extent, got %llu\n", em->block_start);
+		goto out;
+	}
+	if (em->start != offset || em->len != 8192) {
+		test_msg("Unexpected extent wanted start %llu len 8192, got "
+			 "start %llu len %llu\n", offset, em->start, em->len);
+		goto out;
+	}
+	if (em->flags != 0) {
+		test_msg("Unexpected flags set, want 0 have %lu\n", em->flags);
+		goto out;
+	}
+	if (em->orig_start != orig_start) {
+		test_msg("Wrong orig offset, want %llu, have %llu\n",
+			 orig_start, em->orig_start);
+		goto out;
+	}
+	disk_bytenr += (em->start - orig_start);
+	if (em->block_start != disk_bytenr) {
+		test_msg("Wrong block start, want %llu, have %llu\n",
+			 disk_bytenr, em->block_start);
+		goto out;
+	}
+	offset = em->start + em->len;
+	free_extent_map(em);
+
+	/* Prealloc extent */
+	em = btrfs_get_extent(inode, NULL, 0, offset, 4096, 0);
+	if (IS_ERR(em)) {
+		test_msg("Got an error when we shouldn't have\n");
+		goto out;
+	}
+	if (em->block_start >= EXTENT_MAP_LAST_BYTE) {
+		test_msg("Expected a real extent, got %llu\n", em->block_start);
+		goto out;
+	}
+	if (em->start != offset || em->len != 4096) {
+		test_msg("Unexpected extent wanted start %llu len 4096, got "
+			 "start %llu len %llu\n", offset, em->start, em->len);
+		goto out;
+	}
+	if (em->flags != prealloc_only) {
+		test_msg("Unexpected flags set, want %lu have %lu\n",
+			 prealloc_only, em->flags);
+		goto out;
+	}
+	if (em->orig_start != em->start) {
+		test_msg("Wrong orig offset, want %llu, have %llu\n", em->start,
+			 em->orig_start);
+		goto out;
+	}
+	offset = em->start + em->len;
+	free_extent_map(em);
+
+	/* The next 3 are a half written prealloc extent */
+	em = btrfs_get_extent(inode, NULL, 0, offset, 4096, 0);
+	if (IS_ERR(em)) {
+		test_msg("Got an error when we shouldn't have\n");
+		goto out;
+	}
+	if (em->block_start >= EXTENT_MAP_LAST_BYTE) {
+		test_msg("Expected a real extent, got %llu\n", em->block_start);
+		goto out;
+	}
+	if (em->start != offset || em->len != 4096) {
+		test_msg("Unexpected extent wanted start %llu len 4096, got "
+			 "start %llu len %llu\n", offset, em->start, em->len);
+		goto out;
+	}
+	if (em->flags != prealloc_only) {
+		test_msg("Unexpected flags set, want %lu have %lu\n",
+			 prealloc_only, em->flags);
+		goto out;
+	}
+	if (em->orig_start != em->start) {
+		test_msg("Wrong orig offset, want %llu, have %llu\n", em->start,
+			 em->orig_start);
+		goto out;
+	}
+	disk_bytenr = em->block_start;
+	orig_start = em->start;
+	offset = em->start + em->len;
+	free_extent_map(em);
+
+	em = btrfs_get_extent(inode, NULL, 0, offset, 4096, 0);
+	if (IS_ERR(em)) {
+		test_msg("Got an error when we shouldn't have\n");
+		goto out;
+	}
+	if (em->block_start >= EXTENT_MAP_HOLE) {
+		test_msg("Expected a real extent, got %llu\n", em->block_start);
+		goto out;
+	}
+	if (em->start != offset || em->len != 4096) {
+		test_msg("Unexpected extent wanted start %llu len 4096, got "
+			 "start %llu len %llu\n", offset, em->start, em->len);
+		goto out;
+	}
+	if (em->flags != 0) {
+		test_msg("Unexpected flags set, want 0 have %lu\n", em->flags);
+		goto out;
+	}
+	if (em->orig_start != orig_start) {
+		test_msg("Unexpected orig offset, wanted %llu, have %llu\n",
+			 orig_start, em->orig_start);
+		goto out;
+	}
+	if (em->block_start != (disk_bytenr + (em->start - em->orig_start))) {
+		test_msg("Unexpected block start, wanted %llu, have %llu\n",
+			 disk_bytenr + (em->start - em->orig_start),
+			 em->block_start);
+		goto out;
+	}
+	offset = em->start + em->len;
+	free_extent_map(em);
+
+	em = btrfs_get_extent(inode, NULL, 0, offset, 4096, 0);
+	if (IS_ERR(em)) {
+		test_msg("Got an error when we shouldn't have\n");
+		goto out;
+	}
+	if (em->block_start >= EXTENT_MAP_LAST_BYTE) {
+		test_msg("Expected a real extent, got %llu\n", em->block_start);
+		goto out;
+	}
+	if (em->start != offset || em->len != 8192) {
+		test_msg("Unexpected extent wanted start %llu len 8192, got "
+			 "start %llu len %llu\n", offset, em->start, em->len);
+		goto out;
+	}
+	if (em->flags != prealloc_only) {
+		test_msg("Unexpected flags set, want %lu have %lu\n",
+			 prealloc_only, em->flags);
+		goto out;
+	}
+	if (em->orig_start != orig_start) {
+		test_msg("Wrong orig offset, want %llu, have %llu\n", orig_start,
+			 em->orig_start);
+		goto out;
+	}
+	if (em->block_start != (disk_bytenr + (em->start - em->orig_start))) {
+		test_msg("Unexpected block start, wanted %llu, have %llu\n",
+			 disk_bytenr + (em->start - em->orig_start),
+			 em->block_start);
+		goto out;
+	}
+	offset = em->start + em->len;
+	free_extent_map(em);
+
+	/* Now for the compressed extent */
+	em = btrfs_get_extent(inode, NULL, 0, offset, 4096, 0);
+	if (IS_ERR(em)) {
+		test_msg("Got an error when we shouldn't have\n");
+		goto out;
+	}
+	if (em->block_start >= EXTENT_MAP_LAST_BYTE) {
+		test_msg("Expected a real extent, got %llu\n", em->block_start);
+		goto out;
+	}
+	if (em->start != offset || em->len != 8192) {
+		test_msg("Unexpected extent wanted start %llu len 8192, got "
+			 "start %llu len %llu\n", offset, em->start, em->len);
+		goto out;
+	}
+	if (em->flags != compressed_only) {
+		test_msg("Unexpected flags set, want %lu have %lu\n",
+			 compressed_only, em->flags);
+		goto out;
+	}
+	if (em->orig_start != em->start) {
+		test_msg("Wrong orig offset, want %llu, have %llu\n",
+			 em->start, em->orig_start);
+		goto out;
+	}
+	if (em->compress_type != BTRFS_COMPRESS_ZLIB) {
+		test_msg("Unexpected compress type, wanted %d, got %d\n",
+			 BTRFS_COMPRESS_ZLIB, em->compress_type);
+		goto out;
+	}
+	offset = em->start + em->len;
+	free_extent_map(em);
+
+	/* Split compressed extent */
+	em = btrfs_get_extent(inode, NULL, 0, offset, 4096, 0);
+	if (IS_ERR(em)) {
+		test_msg("Got an error when we shouldn't have\n");
+		goto out;
+	}
+	if (em->block_start >= EXTENT_MAP_LAST_BYTE) {
+		test_msg("Expected a real extent, got %llu\n", em->block_start);
+		goto out;
+	}
+	if (em->start != offset || em->len != 4096) {
+		test_msg("Unexpected extent wanted start %llu len 4096, got "
+			 "start %llu len %llu\n", offset, em->start, em->len);
+		goto out;
+	}
+	if (em->flags != compressed_only) {
+		test_msg("Unexpected flags set, want %lu have %lu\n",
+			 compressed_only, em->flags);
+		goto out;
+	}
+	if (em->orig_start != em->start) {
+		test_msg("Wrong orig offset, want %llu, have %llu\n",
+			 em->start, em->orig_start);
+		goto out;
+	}
+	if (em->compress_type != BTRFS_COMPRESS_ZLIB) {
+		test_msg("Unexpected compress type, wanted %d, got %d\n",
+			 BTRFS_COMPRESS_ZLIB, em->compress_type);
+		goto out;
+	}
+	disk_bytenr = em->block_start;
+	orig_start = em->start;
+	offset = em->start + em->len;
+	free_extent_map(em);
+
+	em = btrfs_get_extent(inode, NULL, 0, offset, 4096, 0);
+	if (IS_ERR(em)) {
+		test_msg("Got an error when we shouldn't have\n");
+		goto out;
+	}
+	if (em->block_start >= EXTENT_MAP_LAST_BYTE) {
+		test_msg("Expected a real extent, got %llu\n", em->block_start);
+		goto out;
+	}
+	if (em->start != offset || em->len != 4096) {
+		test_msg("Unexpected extent wanted start %llu len 4096, got "
+			 "start %llu len %llu\n", offset, em->start, em->len);
+		goto out;
+	}
+	if (em->flags != 0) {
+		test_msg("Unexpected flags set, want 0 have %lu\n", em->flags);
+		goto out;
+	}
+	if (em->orig_start != em->start) {
+		test_msg("Wrong orig offset, want %llu, have %llu\n", em->start,
+			 em->orig_start);
+		goto out;
+	}
+	offset = em->start + em->len;
+	free_extent_map(em);
+
+	em = btrfs_get_extent(inode, NULL, 0, offset, 4096, 0);
+	if (IS_ERR(em)) {
+		test_msg("Got an error when we shouldn't have\n");
+		goto out;
+	}
+	if (em->block_start != disk_bytenr) {
+		test_msg("Block start does not match, want %llu got %llu\n",
+			 disk_bytenr, em->block_start);
+		goto out;
+	}
+	if (em->start != offset || em->len != 8192) {
+		test_msg("Unexpected extent wanted start %llu len 8192, got "
+			 "start %llu len %llu\n", offset, em->start, em->len);
+		goto out;
+	}
+	if (em->flags != compressed_only) {
+		test_msg("Unexpected flags set, want %lu have %lu\n",
+			 compressed_only, em->flags);
+		goto out;
+	}
+	if (em->orig_start != orig_start) {
+		test_msg("Wrong orig offset, want %llu, have %llu\n",
+			 em->start, orig_start);
+		goto out;
+	}
+	if (em->compress_type != BTRFS_COMPRESS_ZLIB) {
+		test_msg("Unexpected compress type, wanted %d, got %d\n",
+			 BTRFS_COMPRESS_ZLIB, em->compress_type);
+		goto out;
+	}
+	offset = em->start + em->len;
+	free_extent_map(em);
+
+	/* A hole between regular extents but no hole extent */
+	em = btrfs_get_extent(inode, NULL, 0, offset + 6, 4096, 0);
+	if (IS_ERR(em)) {
+		test_msg("Got an error when we shouldn't have\n");
+		goto out;
+	}
+	if (em->block_start >= EXTENT_MAP_LAST_BYTE) {
+		test_msg("Expected a real extent, got %llu\n", em->block_start);
+		goto out;
+	}
+	if (em->start != offset || em->len != 4096) {
+		test_msg("Unexpected extent wanted start %llu len 4096, got "
+			 "start %llu len %llu\n", offset, em->start, em->len);
+		goto out;
+	}
+	if (em->flags != 0) {
+		test_msg("Unexpected flags set, want 0 have %lu\n", em->flags);
+		goto out;
+	}
+	if (em->orig_start != em->start) {
+		test_msg("Wrong orig offset, want %llu, have %llu\n", em->start,
+			 em->orig_start);
+		goto out;
+	}
+	offset = em->start + em->len;
+	free_extent_map(em);
+
+	em = btrfs_get_extent(inode, NULL, 0, offset, 4096 * 1024, 0);
+	if (IS_ERR(em)) {
+		test_msg("Got an error when we shouldn't have\n");
+		goto out;
+	}
+	if (em->block_start != EXTENT_MAP_HOLE) {
+		test_msg("Expected a hole extent, got %llu\n", em->block_start);
+		goto out;
+	}
+	/*
+	 * Currently we just return a length that we requested rather than the
+	 * length of the actual hole, if this changes we'll have to change this
+	 * test.
+	 */
+	if (em->start != offset || em->len != 12288) {
+		test_msg("Unexpected extent wanted start %llu len 12288, got "
+			 "start %llu len %llu\n", offset, em->start, em->len);
+		goto out;
+	}
+	if (em->flags != vacancy_only) {
+		test_msg("Unexpected flags set, want %lu have %lu\n",
+			 vacancy_only, em->flags);
+		goto out;
+	}
+	if (em->orig_start != em->start) {
+		test_msg("Wrong orig offset, want %llu, have %llu\n", em->start,
+			 em->orig_start);
+		goto out;
+	}
+	offset = em->start + em->len;
+	free_extent_map(em);
+
+	em = btrfs_get_extent(inode, NULL, 0, offset, 4096, 0);
+	if (IS_ERR(em)) {
+		test_msg("Got an error when we shouldn't have\n");
+		goto out;
+	}
+	if (em->block_start >= EXTENT_MAP_LAST_BYTE) {
+		test_msg("Expected a real extent, got %llu\n", em->block_start);
+		goto out;
+	}
+	if (em->start != offset || em->len != 4096) {
+		test_msg("Unexpected extent wanted start %llu len 4096, got "
+			 "start %llu len %llu\n", offset, em->start, em->len);
+		goto out;
+	}
+	if (em->flags != 0) {
+		test_msg("Unexpected flags set, want 0 have %lu\n", em->flags);
+		goto out;
+	}
+	if (em->orig_start != em->start) {
+		test_msg("Wrong orig offset, want %llu, have %llu\n", em->start,
+			 em->orig_start);
+		goto out;
+	}
+	ret = 0;
+out:
+	if (!IS_ERR(em))
+		free_extent_map(em);
+	iput(inode);
+	btrfs_free_dummy_root(root);
+	return ret;
+}
+
+static int test_hole_first(void)
+{
+	struct inode *inode = NULL;
+	struct btrfs_root *root = NULL;
+	struct extent_map *em = NULL;
+	int ret = -ENOMEM;
+
+	inode = btrfs_new_test_inode();
+	if (!inode) {
+		test_msg("Couldn't allocate inode\n");
+		return ret;
+	}
+
+	BTRFS_I(inode)->location.type = BTRFS_INODE_ITEM_KEY;
+	BTRFS_I(inode)->location.objectid = BTRFS_FIRST_FREE_OBJECTID;
+	BTRFS_I(inode)->location.offset = 0;
+
+	root = btrfs_alloc_dummy_root();
+	if (IS_ERR(root)) {
+		test_msg("Couldn't allocate root\n");
+		goto out;
+	}
+
+	root->fs_info = btrfs_alloc_dummy_fs_info();
+	if (!root->fs_info) {
+		test_msg("Couldn't allocate dummy fs info\n");
+		goto out;
+	}
+
+	root->node = alloc_dummy_extent_buffer(0, 4096);
+	if (!root->node) {
+		test_msg("Couldn't allocate dummy buffer\n");
+		goto out;
+	}
+
+	extent_buffer_get(root->node);
+	btrfs_set_header_nritems(root->node, 0);
+	btrfs_set_header_level(root->node, 0);
+	BTRFS_I(inode)->root = root;
+	ret = -EINVAL;
+
+	/*
+	 * Need a blank inode item here just so we don't confuse
+	 * btrfs_get_extent.
+	 */
+	insert_inode_item_key(root);
+	insert_extent(root, 4096, 4096, 4096, 0, 4096, 4096,
+		      BTRFS_FILE_EXTENT_REG, 0, 1);
+	em = btrfs_get_extent(inode, NULL, 0, 0, 8192, 0);
+	if (IS_ERR(em)) {
+		test_msg("Got an error when we shouldn't have\n");
+		goto out;
+	}
+	if (em->block_start != EXTENT_MAP_HOLE) {
+		test_msg("Expected a hole, got %llu\n", em->block_start);
+		goto out;
+	}
+	if (em->start != 0 || em->len != 4096) {
+		test_msg("Unexpected extent wanted start 0 len 4096, got start "
+			 "%llu len %llu\n", em->start, em->len);
+		goto out;
+	}
+	if (em->flags != vacancy_only) {
+		test_msg("Wrong flags, wanted %lu, have %lu\n", vacancy_only,
+			 em->flags);
+		goto out;
+	}
+	free_extent_map(em);
+
+	em = btrfs_get_extent(inode, NULL, 0, 4096, 8192, 0);
+	if (IS_ERR(em)) {
+		test_msg("Got an error when we shouldn't have\n");
+		goto out;
+	}
+	if (em->block_start != 4096) {
+		test_msg("Expected a real extent, got %llu\n", em->block_start);
+		goto out;
+	}
+	if (em->start != 4096 || em->len != 4096) {
+		test_msg("Unexpected extent wanted start 4096 len 4096, got "
+			 "start %llu len %llu\n", em->start, em->len);
+		goto out;
+	}
+	if (em->flags != 0) {
+		test_msg("Unexpected flags set, wanted 0 got %lu\n",
+			 em->flags);
+		goto out;
+	}
+	ret = 0;
+out:
+	if (!IS_ERR(em))
+		free_extent_map(em);
+	iput(inode);
+	btrfs_free_dummy_root(root);
+	return ret;
+}
+
+int btrfs_test_inodes(void)
+{
+	int ret;
+
+	set_bit(EXTENT_FLAG_COMPRESSED, &compressed_only);
+	set_bit(EXTENT_FLAG_VACANCY, &vacancy_only);
+	set_bit(EXTENT_FLAG_PREALLOC, &prealloc_only);
+
+	test_msg("Running btrfs_get_extent tests\n");
+	ret = test_btrfs_get_extent();
+	if (ret)
+		return ret;
+	test_msg("Running hole first btrfs_get_extent test\n");
+	return test_hole_first();
+}

fs/btrfs/tests/qgroup-tests.c

@@ -0,0 +1,470 @@
+/*
+ * Copyright (C) 2013 Facebook.  All rights reserved.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public
+ * License v2 as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public
+ * License along with this program; if not, write to the
+ * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
+ * Boston, MA 021110-1307, USA.
+ */
+
+#include "btrfs-tests.h"
+#include "../ctree.h"
+#include "../transaction.h"
+#include "../disk-io.h"
+#include "../qgroup.h"
+
+static void init_dummy_trans(struct btrfs_trans_handle *trans)
+{
+	memset(trans, 0, sizeof(*trans));
+	trans->transid = 1;
+	INIT_LIST_HEAD(&trans->qgroup_ref_list);
+	trans->type = __TRANS_DUMMY;
+}
+
+static int insert_normal_tree_ref(struct btrfs_root *root, u64 bytenr,
+				  u64 num_bytes, u64 parent, u64 root_objectid)
+{
+	struct btrfs_trans_handle trans;
+	struct btrfs_extent_item *item;
+	struct btrfs_extent_inline_ref *iref;
+	struct btrfs_tree_block_info *block_info;
+	struct btrfs_path *path;
+	struct extent_buffer *leaf;
+	struct btrfs_key ins;
+	u32 size = sizeof(*item) + sizeof(*iref) + sizeof(*block_info);
+	int ret;
+
+	init_dummy_trans(&trans);
+
+	ins.objectid = bytenr;
+	ins.type = BTRFS_EXTENT_ITEM_KEY;
+	ins.offset = num_bytes;
+
+	path = btrfs_alloc_path();
+	if (!path) {
+		test_msg("Couldn't allocate path\n");
+		return -ENOMEM;
+	}
+
+	path->leave_spinning = 1;
+	ret = btrfs_insert_empty_item(&trans, root, path, &ins, size);
+	if (ret) {
+		test_msg("Couldn't insert ref %d\n", ret);
+		btrfs_free_path(path);
+		return ret;
+	}
+
+	leaf = path->nodes[0];
+	item = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
+	btrfs_set_extent_refs(leaf, item, 1);
+	btrfs_set_extent_generation(leaf, item, 1);
+	btrfs_set_extent_flags(leaf, item, BTRFS_EXTENT_FLAG_TREE_BLOCK);
+	block_info = (struct btrfs_tree_block_info *)(item + 1);
+	btrfs_set_tree_block_level(leaf, block_info, 1);
+	iref = (struct btrfs_extent_inline_ref *)(block_info + 1);
+	if (parent > 0) {
+		btrfs_set_extent_inline_ref_type(leaf, iref,
+						 BTRFS_SHARED_BLOCK_REF_KEY);
+		btrfs_set_extent_inline_ref_offset(leaf, iref, parent);
+	} else {
+		btrfs_set_extent_inline_ref_type(leaf, iref, BTRFS_TREE_BLOCK_REF_KEY);
+		btrfs_set_extent_inline_ref_offset(leaf, iref, root_objectid);
+	}
+	btrfs_free_path(path);
+	return 0;
+}
+
+static int add_tree_ref(struct btrfs_root *root, u64 bytenr, u64 num_bytes,
+			u64 parent, u64 root_objectid)
+{
+	struct btrfs_trans_handle trans;
+	struct btrfs_extent_item *item;
+	struct btrfs_path *path;
+	struct btrfs_key key;
+	u64 refs;
+	int ret;
+
+	init_dummy_trans(&trans);
+
+	key.objectid = bytenr;
+	key.type = BTRFS_EXTENT_ITEM_KEY;
+	key.offset = num_bytes;
+
+	path = btrfs_alloc_path();
+	if (!path) {
+		test_msg("Couldn't allocate path\n");
+		return -ENOMEM;
+	}
+
+	path->leave_spinning = 1;
+	ret = btrfs_search_slot(&trans, root, &key, path, 0, 1);
+	if (ret) {
+		test_msg("Couldn't find extent ref\n");
+		btrfs_free_path(path);
+		return ret;
+	}
+
+	item = btrfs_item_ptr(path->nodes[0], path->slots[0],
+			      struct btrfs_extent_item);
+	refs = btrfs_extent_refs(path->nodes[0], item);
+	btrfs_set_extent_refs(path->nodes[0], item, refs + 1);
+	btrfs_release_path(path);
+
+	key.objectid = bytenr;
+	if (parent) {
+		key.type = BTRFS_SHARED_BLOCK_REF_KEY;
+		key.offset = parent;
+	} else {
+		key.type = BTRFS_TREE_BLOCK_REF_KEY;
+		key.offset = root_objectid;
+	}
+
+	ret = btrfs_insert_empty_item(&trans, root, path, &key, 0);
+	if (ret)
+		test_msg("Failed to insert backref\n");
+	btrfs_free_path(path);
+	return ret;
+}
+
+static int remove_extent_item(struct btrfs_root *root, u64 bytenr,
+			      u64 num_bytes)
+{
+	struct btrfs_trans_handle trans;
+	struct btrfs_key key;
+	struct btrfs_path *path;
+	int ret;
+
+	init_dummy_trans(&trans);
+
+	key.objectid = bytenr;
+	key.type = BTRFS_EXTENT_ITEM_KEY;
+	key.offset = num_bytes;
+
+	path = btrfs_alloc_path();
+	if (!path) {
+		test_msg("Couldn't allocate path\n");
+		return -ENOMEM;
+	}
+	path->leave_spinning = 1;
+
+	ret = btrfs_search_slot(&trans, root, &key, path, -1, 1);
+	if (ret) {
+		test_msg("Didn't find our key %d\n", ret);
+		btrfs_free_path(path);
+		return ret;
+	}
+	btrfs_del_item(&trans, root, path);
+	btrfs_free_path(path);
+	return 0;
+}
+
+static int remove_extent_ref(struct btrfs_root *root, u64 bytenr,
+			     u64 num_bytes, u64 parent, u64 root_objectid)
+{
+	struct btrfs_trans_handle trans;
+	struct btrfs_extent_item *item;
+	struct btrfs_path *path;
+	struct btrfs_key key;
+	u64 refs;
+	int ret;
+
+	init_dummy_trans(&trans);
+
+	key.objectid = bytenr;
+	key.type = BTRFS_EXTENT_ITEM_KEY;
+	key.offset = num_bytes;
+
+	path = btrfs_alloc_path();
+	if (!path) {
+		test_msg("Couldn't allocate path\n");
+		return -ENOMEM;
+	}
+
+	path->leave_spinning = 1;
+	ret = btrfs_search_slot(&trans, root, &key, path, 0, 1);
+	if (ret) {
+		test_msg("Couldn't find extent ref\n");
+		btrfs_free_path(path);
+		return ret;
+	}
+
+	item = btrfs_item_ptr(path->nodes[0], path->slots[0],
+			      struct btrfs_extent_item);
+	refs = btrfs_extent_refs(path->nodes[0], item);
+	btrfs_set_extent_refs(path->nodes[0], item, refs - 1);
+	btrfs_release_path(path);
+
+	key.objectid = bytenr;
+	if (parent) {
+		key.type = BTRFS_SHARED_BLOCK_REF_KEY;
+		key.offset = parent;
+	} else {
+		key.type = BTRFS_TREE_BLOCK_REF_KEY;
+		key.offset = root_objectid;
+	}
+
+	ret = btrfs_search_slot(&trans, root, &key, path, -1, 1);
+	if (ret) {
+		test_msg("Couldn't find backref %d\n", ret);
+		btrfs_free_path(path);
+		return ret;
+	}
+	btrfs_del_item(&trans, root, path);
+	btrfs_free_path(path);
+	return ret;
+}
+
+static int test_no_shared_qgroup(struct btrfs_root *root)
+{
+	struct btrfs_trans_handle trans;
+	struct btrfs_fs_info *fs_info = root->fs_info;
+	int ret;
+
+	init_dummy_trans(&trans);
+
+	test_msg("Qgroup basic add\n");
+	ret = btrfs_create_qgroup(NULL, fs_info, 5, NULL);
+	if (ret) {
+		test_msg("Couldn't create a qgroup %d\n", ret);
+		return ret;
+	}
+
+	ret = btrfs_qgroup_record_ref(&trans, fs_info, 5, 4096, 4096,
+				      BTRFS_QGROUP_OPER_ADD_EXCL, 0);
+	if (ret) {
+		test_msg("Couldn't add space to a qgroup %d\n", ret);
+		return ret;
+	}
+
+	ret = insert_normal_tree_ref(root, 4096, 4096, 0, 5);
+	if (ret)
+		return ret;
+
+	ret = btrfs_delayed_qgroup_accounting(&trans, fs_info);
+	if (ret) {
+		test_msg("Delayed qgroup accounting failed %d\n", ret);
+		return ret;
+	}
+
+	if (btrfs_verify_qgroup_counts(fs_info, 5, 4096, 4096)) {
+		test_msg("Qgroup counts didn't match expected values\n");
+		return -EINVAL;
+	}
+
+	ret = remove_extent_item(root, 4096, 4096);
+	if (ret)
+		return -EINVAL;
+
+	ret = btrfs_qgroup_record_ref(&trans, fs_info, 5, 4096, 4096,
+				      BTRFS_QGROUP_OPER_SUB_EXCL, 0);
+	if (ret) {
+		test_msg("Couldn't remove space from the qgroup %d\n", ret);
+		return -EINVAL;
+	}
+
+	ret = btrfs_delayed_qgroup_accounting(&trans, fs_info);
+	if (ret) {
+		test_msg("Qgroup accounting failed %d\n", ret);
+		return -EINVAL;
+	}
+
+	if (btrfs_verify_qgroup_counts(fs_info, 5, 0, 0)) {
+		test_msg("Qgroup counts didn't match expected values\n");
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
+/*
+ * Add a ref for two different roots to make sure the shared value comes out
+ * right, also remove one of the roots and make sure the exclusive count is
+ * adjusted properly.
+ */
+static int test_multiple_refs(struct btrfs_root *root)
+{
+	struct btrfs_trans_handle trans;
+	struct btrfs_fs_info *fs_info = root->fs_info;
+	int ret;
+
+	init_dummy_trans(&trans);
+
+	test_msg("Qgroup multiple refs test\n");
+
+	/* We have 5 created already from the previous test */
+	ret = btrfs_create_qgroup(NULL, fs_info, 256, NULL);
+	if (ret) {
+		test_msg("Couldn't create a qgroup %d\n", ret);
+		return ret;
+	}
+
+	ret = insert_normal_tree_ref(root, 4096, 4096, 0, 5);
+	if (ret)
+		return ret;
+
+	ret = btrfs_qgroup_record_ref(&trans, fs_info, 5, 4096, 4096,
+				      BTRFS_QGROUP_OPER_ADD_EXCL, 0);
+	if (ret) {
+		test_msg("Couldn't add space to a qgroup %d\n", ret);
+		return ret;
+	}
+
+	ret = btrfs_delayed_qgroup_accounting(&trans, fs_info);
+	if (ret) {
+		test_msg("Delayed qgroup accounting failed %d\n", ret);
+		return ret;
+	}
+
+	if (btrfs_verify_qgroup_counts(fs_info, 5, 4096, 4096)) {
+		test_msg("Qgroup counts didn't match expected values\n");
+		return -EINVAL;
+	}
+
+	ret = add_tree_ref(root, 4096, 4096, 0, 256);
+	if (ret)
+		return ret;
+
+	ret = btrfs_qgroup_record_ref(&trans, fs_info, 256, 4096, 4096,
+				      BTRFS_QGROUP_OPER_ADD_SHARED, 0);
+	if (ret) {
+		test_msg("Qgroup record ref failed %d\n", ret);
+		return ret;
+	}
+
+	ret = btrfs_delayed_qgroup_accounting(&trans, fs_info);
+	if (ret) {
+		test_msg("Qgroup accounting failed %d\n", ret);
+		return ret;
+	}
+
+	if (btrfs_verify_qgroup_counts(fs_info, 5, 4096, 0)) {
+		test_msg("Qgroup counts didn't match expected values\n");
+		return -EINVAL;
+	}
+
+	if (btrfs_verify_qgroup_counts(fs_info, 256, 4096, 0)) {
+		test_msg("Qgroup counts didn't match expected values\n");
+		return -EINVAL;
+	}
+
+	ret = remove_extent_ref(root, 4096, 4096, 0, 256);
+	if (ret)
+		return ret;
+
+	ret = btrfs_qgroup_record_ref(&trans, fs_info, 256, 4096, 4096,
+				      BTRFS_QGROUP_OPER_SUB_SHARED, 0);
+	if (ret) {
+		test_msg("Qgroup record ref failed %d\n", ret);
+		return ret;
+	}
+
+	ret = btrfs_delayed_qgroup_accounting(&trans, fs_info);
+	if (ret) {
+		test_msg("Qgroup accounting failed %d\n", ret);
+		return ret;
+	}
+
+	if (btrfs_verify_qgroup_counts(fs_info, 256, 0, 0)) {
+		test_msg("Qgroup counts didn't match expected values\n");
+		return -EINVAL;
+	}
+
+	if (btrfs_verify_qgroup_counts(fs_info, 5, 4096, 4096)) {
+		test_msg("Qgroup counts didn't match expected values\n");
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
+int btrfs_test_qgroups(void)
+{
+	struct btrfs_root *root;
+	struct btrfs_root *tmp_root;
+	int ret = 0;
+
+	root = btrfs_alloc_dummy_root();
+	if (IS_ERR(root)) {
+		test_msg("Couldn't allocate root\n");
+		return PTR_ERR(root);
+	}
+
+	root->fs_info = btrfs_alloc_dummy_fs_info();
+	if (!root->fs_info) {
+		test_msg("Couldn't allocate dummy fs info\n");
+		ret = -ENOMEM;
+		goto out;
+	}
+
+	/*
+	 * Can't use bytenr 0, some things freak out
+	 * *cough*backref walking code*cough*
+	 */
+	root->node = alloc_test_extent_buffer(root->fs_info, 4096, 4096);
+	if (!root->node) {
+		test_msg("Couldn't allocate dummy buffer\n");
+		ret = -ENOMEM;
+		goto out;
+	}
+	btrfs_set_header_level(root->node, 0);
+	btrfs_set_header_nritems(root->node, 0);
+	root->alloc_bytenr += 8192;
+
+	tmp_root = btrfs_alloc_dummy_root();
+	if (IS_ERR(tmp_root)) {
+		test_msg("Couldn't allocate a fs root\n");
+		ret = PTR_ERR(tmp_root);
+		goto out;
+	}
+
+	tmp_root->root_key.objectid = 5;
+	root->fs_info->fs_root = tmp_root;
+	ret = btrfs_insert_fs_root(root->fs_info, tmp_root);
+	if (ret) {
+		test_msg("Couldn't insert fs root %d\n", ret);
+		goto out;
+	}
+
+	tmp_root = btrfs_alloc_dummy_root();
+	if (IS_ERR(tmp_root)) {
+		test_msg("Couldn't allocate a fs root\n");
+		ret = PTR_ERR(tmp_root);
+		goto out;
+	}
+
+	tmp_root->root_key.objectid = 256;
+	ret = btrfs_insert_fs_root(root->fs_info, tmp_root);
+	if (ret) {
+		test_msg("Couldn't insert fs root %d\n", ret);
+		goto out;
+	}
+
+	/* We are using this root as our extent root */
+	root->fs_info->extent_root = root;
+
+	/*
+	 * Some of the paths we test assume we have a filled out fs_info, so we
+	 * just need to addt he root in there so we don't panic.
+	 */
+	root->fs_info->tree_root = root;
+	root->fs_info->quota_root = root;
+	root->fs_info->quota_enabled = 1;
+
+	test_msg("Running qgroup tests\n");
+	ret = test_no_shared_qgroup(root);
+	if (ret)
+		goto out;
+	ret = test_multiple_refs(root);
+out:
+	btrfs_free_dummy_root(root);
+	return ret;
+}