Btrfs: add tests for btrfs_get_extent

I'm going to be removing hole extents in the near future so I wanted to make a
sanity test for btrfs_get_extent to make sure I don't break anything in the
meantime.  This patch just puts btrfs_get_extent through its paces by giving it
a completely unreasonable mapping to look at and make sure it is giving us back
maps that make sense.  Thanks,
Signed-off-by: Josef Bacik <jbacik@fusionio.com>
Signed-off-by: Chris Mason <chris.mason@fusionio.com>

fs/btrfs/Makefile

@@ -15,4 +15,5 @@ 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/btrfs-tests.o tests/extent-io-tests.o
+	tests/extent-buffer-tests.o tests/btrfs-tests.o \
+	tests/extent-io-tests.o tests/inode-tests.o

fs/btrfs/ctree.h

@@ -4034,5 +4034,9 @@ static inline int btrfs_defrag_cancelled(struct btrfs_fs_info *fs_info)
 	return signal_pending(current);
 }
 
+/* Sanity test specific functions */
+#ifdef CONFIG_BTRFS_FS_RUN_SANITY_TESTS
+void btrfs_test_destroy_inode(struct inode *inode);
+#endif
 
 #endif

fs/btrfs/inode.c

@@ -7795,6 +7795,14 @@ struct inode *btrfs_alloc_inode(struct super_block *sb)
 	return inode;
 }
 
+#ifdef CONFIG_BTRFS_FS_RUN_SANITY_TESTS
+void btrfs_test_destroy_inode(struct inode *inode)
+{
+	btrfs_drop_extent_cache(inode, 0, (u64)-1, 0);
+	kmem_cache_free(btrfs_inode_cachep, BTRFS_I(inode));
+}
+#endif
+
 static void btrfs_i_callback(struct rcu_head *head)
 {
 	struct inode *inode = container_of(head, struct inode, i_rcu);

fs/btrfs/super.c

@@ -1802,6 +1802,9 @@ static int btrfs_run_sanity_tests(void)
 	if (ret)
 		goto out;
 	ret = btrfs_test_extent_io();
+	if (ret)
+		goto out;
+	ret = btrfs_test_inodes();
 out:
 	btrfs_destroy_test_fs();
 	return ret;

fs/btrfs/tests/btrfs-tests.c

@@ -24,11 +24,17 @@
 
 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:", NULL, NULL, BTRFS_TEST_MAGIC);
+	return mount_pseudo(fs_type, "btrfs_test:", &btrfs_test_super_ops,
+			    NULL, BTRFS_TEST_MAGIC);
 }
 
 static struct file_system_type test_type = {

fs/btrfs/tests/btrfs-tests.h

@@ -26,6 +26,7 @@
 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_init_test_fs(void);
 void btrfs_destroy_test_fs(void);
 struct inode *btrfs_new_test_inode(void);
@@ -49,6 +50,10 @@ static inline int btrfs_test_extent_io(void)
 {
 	return 0;
 }
+static inline int btrfs_test_inodes(void)
+{
+	return 0;
+}
 #endif
 
 #endif