Btrfs: add tests for find_lock_delalloc_range

So both Liu and I made huge messes of find_lock_delalloc_range trying to fix
stuff, me first by fixing extent size, then him by fixing something I broke and
then me again telling him to fix it a different way.  So this is obviously a
candidate for some testing.  This patch adds a pseudo fs so we can allocate fake
inodes for tests that need an inode or pages.  Then it addes a bunch of tests to
make sure find_lock_delalloc_range is acting the way it is supposed to.  With
this patch and all of our previous patches to find_lock_delalloc_range I am sure
it is working as expected now.  Thanks,

Signed-off-by: Josef Bacik <jbacik@fusionio.com>
Signed-off-by: Chris Mason <chris.mason@fusionio.com>

Author: Josef Bacik

fs/btrfs/Makefile

@@ -15,4 +15,4 @@ btrfs-$(CONFIG_BTRFS_FS_POSIX_ACL) += acl.o
 btrfs-$(CONFIG_BTRFS_FS_CHECK_INTEGRITY) += check-integrity.o
 
 btrfs-$(CONFIG_BTRFS_FS_RUN_SANITY_TESTS) += tests/free-space-tests.o \
-	tests/extent-buffer-tests.o
+	tests/extent-buffer-tests.o tests/btrfs-tests.o tests/extent-io-tests.o

fs/btrfs/ctree.h

@@ -47,6 +47,12 @@ extern struct kmem_cache *btrfs_path_cachep;
 extern struct kmem_cache *btrfs_free_space_cachep;
 struct btrfs_ordered_sum;
 
+#ifdef CONFIG_BTRFS_FS_RUN_SANITY_TESTS
+#define STATIC noinline
+#else
+#define STATIC static noinline
+#endif
+
 #define BTRFS_MAGIC 0x4D5F53665248425FULL /* ascii _BHRfS_M, no null */
 
 #define BTRFS_MAX_MIRRORS 3

fs/btrfs/extent_io.c

@@ -1598,11 +1598,10 @@ static noinline int lock_delalloc_pages(struct inode *inode,
  *
  * 1 is returned if we find something, 0 if nothing was in the tree
  */
-static noinline u64 find_lock_delalloc_range(struct inode *inode,
-					     struct extent_io_tree *tree,
-					     struct page *locked_page,
-					     u64 *start, u64 *end,
-					     u64 max_bytes)
+STATIC u64 find_lock_delalloc_range(struct inode *inode,
+				    struct extent_io_tree *tree,
+				    struct page *locked_page, u64 *start,
+				    u64 *end, u64 max_bytes)
 {
 	u64 delalloc_start;
 	u64 delalloc_end;

fs/btrfs/extent_io.h

@@ -345,4 +345,10 @@ int repair_io_failure(struct btrfs_fs_info *fs_info, u64 start,
 int end_extent_writepage(struct page *page, int err, u64 start, u64 end);
 int repair_eb_io_failure(struct btrfs_root *root, struct extent_buffer *eb,
 			 int mirror_num);
+#ifdef CONFIG_BTRFS_FS_RUN_SANITY_TESTS
+noinline u64 find_lock_delalloc_range(struct inode *inode,
+				      struct extent_io_tree *tree,
+				      struct page *locked_page, u64 *start,
+				      u64 *end, u64 max_bytes);
+#endif
 #endif

fs/btrfs/super.c

@@ -1791,10 +1791,20 @@ static int btrfs_run_sanity_tests(void)
 {
 	int ret;
 
-	ret = btrfs_test_free_space_cache();
+	ret = btrfs_init_test_fs();
 	if (ret)
 		return ret;
-	return btrfs_test_extent_buffer_operations();
+
+	ret = btrfs_test_free_space_cache();
+	if (ret)
+		goto out;
+	ret = btrfs_test_extent_buffer_operations();
+	if (ret)
+		goto out;
+	ret = btrfs_test_extent_io();
+out:
+	btrfs_destroy_test_fs();
+	return ret;
 }
 
 static int __init init_btrfs_fs(void)

fs/btrfs/tests/btrfs-tests.c

@@ -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.
+ */
+
+#include <linux/fs.h>
+#include <linux/mount.h>
+#include <linux/magic.h>
+#include "btrfs-tests.h"
+#include "../ctree.h"
+
+static struct vfsmount *test_mnt = NULL;
+
+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:", NULL, 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);
+}

fs/btrfs/tests/btrfs-tests.h

@@ -25,6 +25,10 @@
 
 int btrfs_test_free_space_cache(void);
 int btrfs_test_extent_buffer_operations(void);
+int btrfs_test_extent_io(void);
+int btrfs_init_test_fs(void);
+void btrfs_destroy_test_fs(void);
+struct inode *btrfs_new_test_inode(void);
 #else
 static inline int btrfs_test_free_space_cache(void)
 {
@@ -34,6 +38,17 @@ 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;
+}
 #endif
 
 #endif