Btrfs: Create orphan inode records to prevent lost files after a crash

Signed-off-by: Chris Mason <chris.mason@oracle.com>

fs/btrfs/Makefile

@@ -6,7 +6,7 @@ btrfs-y := super.o ctree.o extent-tree.o print-tree.o root-tree.o dir-item.o \
 	   hash.o file-item.o inode-item.o inode-map.o disk-io.o \
 	   transaction.o bit-radix.o inode.o file.o tree-defrag.o \
 	   extent_map.o sysfs.o struct-funcs.o xattr.o ordered-data.o \
-	   extent_io.o volumes.o async-thread.o ioctl.o locking.o
+	   extent_io.o volumes.o async-thread.o ioctl.o locking.o orphan.o
 
 btrfs-$(CONFIG_FS_POSIX_ACL)	+= acl.o
 else

fs/btrfs/btrfs_inode.h

@@ -39,6 +39,9 @@ struct btrfs_inode {
 	struct posix_acl *i_acl;
 	struct posix_acl *i_default_acl;
 
+	/* for keeping track of orphaned inodes */
+	struct list_head i_orphan;
+
 	/*
 	 * transid of the trans_handle that last modified this inode
 	 */

fs/btrfs/ctree.c

@@ -2622,7 +2622,7 @@ int btrfs_insert_empty_items(struct btrfs_trans_handle *trans,
 		total_data += data_size[i];
 	}
 
-	total_size = total_data + (nr - 1) * sizeof(struct btrfs_item);
+	total_size = total_data + (nr * sizeof(struct btrfs_item));
 	ret = btrfs_search_slot(trans, root, cpu_key, path, total_size, 1);
 	if (ret == 0) {
 		return -EEXIST;

fs/btrfs/ctree.h

@@ -74,6 +74,9 @@ struct btrfs_ordered_sum;
 /* directory objectid inside the root tree */
 #define BTRFS_ROOT_TREE_DIR_OBJECTID 6ULL
 
+/* orhpan objectid for tracking unlinked/truncated files */
+#define BTRFS_ORPHAN_OBJECTID -5ULL
+
 /*
  * All files have objectids higher than this.
  */
@@ -646,6 +649,9 @@ struct btrfs_root {
 
 	/* the dirty list is only used by non-reference counted roots */
 	struct list_head dirty_list;
+
+	spinlock_t orphan_lock;
+	struct list_head orphan_list;
 };
 
 /*
@@ -657,6 +663,7 @@ struct btrfs_root {
 #define BTRFS_INODE_ITEM_KEY		1
 #define BTRFS_INODE_REF_KEY		2
 #define BTRFS_XATTR_ITEM_KEY		8
+#define BTRFS_ORPHAN_ITEM_KEY		9
 /* reserve 2-15 close to the inode for later flexibility */
 
 /*
@@ -1560,6 +1567,13 @@ struct btrfs_dir_item *btrfs_lookup_xattr(struct btrfs_trans_handle *trans,
 					  struct btrfs_path *path, u64 dir,
 					  const char *name, u16 name_len,
 					  int mod);
+
+/* orphan.c */
+int btrfs_insert_orphan_item(struct btrfs_trans_handle *trans,
+			     struct btrfs_root *root, u64 offset);
+int btrfs_del_orphan_item(struct btrfs_trans_handle *trans,
+			  struct btrfs_root *root, u64 offset);
+
 /* inode-map.c */
 int btrfs_find_free_objectid(struct btrfs_trans_handle *trans,
 			     struct btrfs_root *fs_root,

fs/btrfs/disk-io.c

@@ -732,7 +732,9 @@ static int __setup_root(u32 nodesize, u32 leafsize, u32 sectorsize,
 	root->in_sysfs = 0;
 
 	INIT_LIST_HEAD(&root->dirty_list);
+	INIT_LIST_HEAD(&root->orphan_list);
 	spin_lock_init(&root->node_lock);
+	spin_lock_init(&root->orphan_lock);
 	mutex_init(&root->objectid_mutex);
 	memset(&root->root_key, 0, sizeof(root->root_key));
 	memset(&root->root_item, 0, sizeof(root->root_item));

fs/btrfs/orphan.c

+/*
+ * Copyright (C) 2008 Red Hat.  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 "ctree.h"
+#include "disk-io.h"
+
+int btrfs_insert_orphan_item(struct btrfs_trans_handle *trans,
+			     struct btrfs_root *root, u64 offset)
+{
+	struct btrfs_path *path;
+	struct btrfs_key key;
+	int ret = 0;
+
+	key.objectid = BTRFS_ORPHAN_OBJECTID;
+	btrfs_set_key_type(&key, BTRFS_ORPHAN_ITEM_KEY);
+	key.offset = offset;
+
+	path = btrfs_alloc_path();
+	if (!path)
+		return -ENOMEM;
+
+	ret = btrfs_insert_empty_item(trans, root, path, &key, 0);
+
+	btrfs_free_path(path);
+	return ret;
+}
+
+int btrfs_del_orphan_item(struct btrfs_trans_handle *trans,
+			  struct btrfs_root *root, u64 offset)
+{
+	struct btrfs_path *path;
+	struct btrfs_key key;
+	int ret = 0;
+
+	key.objectid = BTRFS_ORPHAN_OBJECTID;
+	btrfs_set_key_type(&key, BTRFS_ORPHAN_ITEM_KEY);
+	key.offset = offset;
+
+	path = btrfs_alloc_path();
+	if (!path)
+		return -ENOMEM;
+
+	ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
+	if (ret)
+		goto out;
+
+	ret = btrfs_del_item(trans, root, path);
+
+out:
+	btrfs_free_path(path);
+	return ret;
+}