1 files changed, 366 insertions, 0 deletions
diff --git a/fs/btrfs/root-tree.c b/fs/btrfs/root-tree.c
new file mode 100644
index 000000000000..b48650de4472
--- /dev/null
+++ b/fs/btrfs/root-tree.c
@@ -0,0 +1,366 @@
+/*
+ * Copyright (C) 2007 Oracle.  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 "transaction.h"
+#include "disk-io.h"
+#include "print-tree.h"
+
+/*
+ *  search forward for a root, starting with objectid 'search_start'
+ *  if a root key is found, the objectid we find is filled into 'found_objectid'
+ *  and 0 is returned.  < 0 is returned on error, 1 if there is nothing
+ *  left in the tree.
+ */
+int btrfs_search_root(struct btrfs_root *root, u64 search_start,
+		      u64 *found_objectid)
+{
+	struct btrfs_path *path;
+	struct btrfs_key search_key;
+	int ret;
+
+	root = root->fs_info->tree_root;
+	search_key.objectid = search_start;
+	search_key.type = (u8)-1;
+	search_key.offset = (u64)-1;
+
+	path = btrfs_alloc_path();
+	BUG_ON(!path);
+again:
+	ret = btrfs_search_slot(NULL, root, &search_key, path, 0, 0);
+	if (ret < 0)
+		goto out;
+	if (ret == 0) {
+		ret = 1;
+		goto out;
+	}
+	if (path->slots[0] >= btrfs_header_nritems(path->nodes[0])) {
+		ret = btrfs_next_leaf(root, path);
+		if (ret)
+			goto out;
+	}
+	btrfs_item_key_to_cpu(path->nodes[0], &search_key, path->slots[0]);
+	if (search_key.type != BTRFS_ROOT_ITEM_KEY) {
+		search_key.offset++;
+		btrfs_release_path(root, path);
+		goto again;
+	}
+	ret = 0;
+	*found_objectid = search_key.objectid;
+
+out:
+	btrfs_free_path(path);
+	return ret;
+}
+
+/*
+ * lookup the root with the highest offset for a given objectid.  The key we do
+ * find is copied into 'key'.  If we find something return 0, otherwise 1, < 0
+ * on error.
+ */
+int btrfs_find_last_root(struct btrfs_root *root, u64 objectid,
+			struct btrfs_root_item *item, struct btrfs_key *key)
+{
+	struct btrfs_path *path;
+	struct btrfs_key search_key;
+	struct btrfs_key found_key;
+	struct extent_buffer *l;
+	int ret;
+	int slot;
+
+	search_key.objectid = objectid;
+	search_key.type = BTRFS_ROOT_ITEM_KEY;
+	search_key.offset = (u64)-1;
+
+	path = btrfs_alloc_path();
+	BUG_ON(!path);
+	ret = btrfs_search_slot(NULL, root, &search_key, path, 0, 0);
+	if (ret < 0)
+		goto out;
+
+	BUG_ON(ret == 0);
+	l = path->nodes[0];
+	BUG_ON(path->slots[0] == 0);
+	slot = path->slots[0] - 1;
+	btrfs_item_key_to_cpu(l, &found_key, slot);
+	if (found_key.objectid != objectid) {
+		ret = 1;
+		goto out;
+	}
+	read_extent_buffer(l, item, btrfs_item_ptr_offset(l, slot),
+			   sizeof(*item));
+	memcpy(key, &found_key, sizeof(found_key));
+	ret = 0;
+out:
+	btrfs_free_path(path);
+	return ret;
+}
+
+/*
+ * copy the data in 'item' into the btree
+ */
+int btrfs_update_root(struct btrfs_trans_handle *trans, struct btrfs_root
+		      *root, struct btrfs_key *key, struct btrfs_root_item
+		      *item)
+{
+	struct btrfs_path *path;
+	struct extent_buffer *l;
+	int ret;
+	int slot;
+	unsigned long ptr;
+
+	path = btrfs_alloc_path();
+	BUG_ON(!path);
+	ret = btrfs_search_slot(trans, root, key, path, 0, 1);
+	if (ret < 0)
+		goto out;
+
+	if (ret != 0) {
+		btrfs_print_leaf(root, path->nodes[0]);
+		printk(KERN_CRIT "unable to update root key %llu %u %llu\n",
+		       (unsigned long long)key->objectid, key->type,
+		       (unsigned long long)key->offset);
+		BUG_ON(1);
+	}
+
+	l = path->nodes[0];
+	slot = path->slots[0];
+	ptr = btrfs_item_ptr_offset(l, slot);
+	write_extent_buffer(l, item, ptr, sizeof(*item));
+	btrfs_mark_buffer_dirty(path->nodes[0]);
+out:
+	btrfs_release_path(root, path);
+	btrfs_free_path(path);
+	return ret;
+}
+
+int btrfs_insert_root(struct btrfs_trans_handle *trans, struct btrfs_root
+		      *root, struct btrfs_key *key, struct btrfs_root_item
+		      *item)
+{
+	int ret;
+	ret = btrfs_insert_item(trans, root, key, item, sizeof(*item));
+	return ret;
+}
+
+/*
+ * at mount time we want to find all the old transaction snapshots that were in
+ * the process of being deleted if we crashed.  This is any root item with an
+ * offset lower than the latest root.  They need to be queued for deletion to
+ * finish what was happening when we crashed.
+ */
+int btrfs_find_dead_roots(struct btrfs_root *root, u64 objectid,
+			  struct btrfs_root *latest)
+{
+	struct btrfs_root *dead_root;
+	struct btrfs_item *item;
+	struct btrfs_root_item *ri;
+	struct btrfs_key key;
+	struct btrfs_key found_key;
+	struct btrfs_path *path;
+	int ret;
+	u32 nritems;
+	struct extent_buffer *leaf;
+	int slot;
+
+	key.objectid = objectid;
+	btrfs_set_key_type(&key, BTRFS_ROOT_ITEM_KEY);
+	key.offset = 0;
+	path = btrfs_alloc_path();
+	if (!path)
+		return -ENOMEM;
+
+again:
+	ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
+	if (ret < 0)
+		goto err;
+	while (1) {
+		leaf = path->nodes[0];
+		nritems = btrfs_header_nritems(leaf);
+		slot = path->slots[0];
+		if (slot >= nritems) {
+			ret = btrfs_next_leaf(root, path);
+			if (ret)
+				break;
+			leaf = path->nodes[0];
+			nritems = btrfs_header_nritems(leaf);
+			slot = path->slots[0];
+		}
+		item = btrfs_item_nr(leaf, slot);
+		btrfs_item_key_to_cpu(leaf, &key, slot);
+		if (btrfs_key_type(&key) != BTRFS_ROOT_ITEM_KEY)
+			goto next;
+
+		if (key.objectid < objectid)
+			goto next;
+
+		if (key.objectid > objectid)
+			break;
+
+		ri = btrfs_item_ptr(leaf, slot, struct btrfs_root_item);
+		if (btrfs_disk_root_refs(leaf, ri) != 0)
+			goto next;
+
+		memcpy(&found_key, &key, sizeof(key));
+		key.offset++;
+		btrfs_release_path(root, path);
+		dead_root =
+			btrfs_read_fs_root_no_radix(root->fs_info->tree_root,
+						    &found_key);
+		if (IS_ERR(dead_root)) {
+			ret = PTR_ERR(dead_root);
+			goto err;
+		}
+
+		if (objectid == BTRFS_TREE_RELOC_OBJECTID)
+			ret = btrfs_add_dead_reloc_root(dead_root);
+		else
+			ret = btrfs_add_dead_root(dead_root, latest);
+		if (ret)
+			goto err;
+		goto again;
+next:
+		slot++;
+		path->slots[0]++;
+	}
+	ret = 0;
+err:
+	btrfs_free_path(path);
+	return ret;
+}
+
+/* drop the root item for 'key' from 'root' */
+int btrfs_del_root(struct btrfs_trans_handle *trans, struct btrfs_root *root,
+		   struct btrfs_key *key)
+{
+	struct btrfs_path *path;
+	int ret;
+	u32 refs;
+	struct btrfs_root_item *ri;
+	struct extent_buffer *leaf;
+
+	path = btrfs_alloc_path();
+	BUG_ON(!path);
+	ret = btrfs_search_slot(trans, root, key, path, -1, 1);
+	if (ret < 0)
+		goto out;
+
+	BUG_ON(ret != 0);
+	leaf = path->nodes[0];
+	ri = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_root_item);
+
+	refs = btrfs_disk_root_refs(leaf, ri);
+	BUG_ON(refs != 0);
+	ret = btrfs_del_item(trans, root, path);
+out:
+	btrfs_release_path(root, path);
+	btrfs_free_path(path);
+	return ret;
+}
+
+#if 0 /* this will get used when snapshot deletion is implemented */
+int btrfs_del_root_ref(struct btrfs_trans_handle *trans,
+		       struct btrfs_root *tree_root,
+		       u64 root_id, u8 type, u64 ref_id)
+{
+	struct btrfs_key key;
+	int ret;
+	struct btrfs_path *path;
+
+	path = btrfs_alloc_path();
+
+	key.objectid = root_id;
+	key.type = type;
+	key.offset = ref_id;
+
+	ret = btrfs_search_slot(trans, tree_root, &key, path, -1, 1);
+	BUG_ON(ret);
+
+	ret = btrfs_del_item(trans, tree_root, path);
+	BUG_ON(ret);
+
+	btrfs_free_path(path);
+	return ret;
+}
+#endif
+
+int btrfs_find_root_ref(struct btrfs_root *tree_root,
+		   struct btrfs_path *path,
+		   u64 root_id, u64 ref_id)
+{
+	struct btrfs_key key;
+	int ret;
+
+	key.objectid = root_id;
+	key.type = BTRFS_ROOT_REF_KEY;
+	key.offset = ref_id;
+
+	ret = btrfs_search_slot(NULL, tree_root, &key, path, 0, 0);
+	return ret;
+}
+
+
+/*
+ * add a btrfs_root_ref item.  type is either BTRFS_ROOT_REF_KEY
+ * or BTRFS_ROOT_BACKREF_KEY.
+ *
+ * The dirid, sequence, name and name_len refer to the directory entry
+ * that is referencing the root.
+ *
+ * For a forward ref, the root_id is the id of the tree referencing
+ * the root and ref_id is the id of the subvol  or snapshot.
+ *
+ * For a back ref the root_id is the id of the subvol or snapshot and
+ * ref_id is the id of the tree referencing it.
+ */
+int btrfs_add_root_ref(struct btrfs_trans_handle *trans,
+		       struct btrfs_root *tree_root,
+		       u64 root_id, u8 type, u64 ref_id,
+		       u64 dirid, u64 sequence,
+		       const char *name, int name_len)
+{
+	struct btrfs_key key;
+	int ret;
+	struct btrfs_path *path;
+	struct btrfs_root_ref *ref;
+	struct extent_buffer *leaf;
+	unsigned long ptr;
+
+
+	path = btrfs_alloc_path();
+
+	key.objectid = root_id;
+	key.type = type;
+	key.offset = ref_id;
+
+	ret = btrfs_insert_empty_item(trans, tree_root, path, &key,
+				      sizeof(*ref) + name_len);
+	BUG_ON(ret);
+
+	leaf = path->nodes[0];
+	ref = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_root_ref);
+	btrfs_set_root_ref_dirid(leaf, ref, dirid);
+	btrfs_set_root_ref_sequence(leaf, ref, sequence);
+	btrfs_set_root_ref_name_len(leaf, ref, name_len);
+	ptr = (unsigned long)(ref + 1);
+	write_extent_buffer(leaf, name, ptr, name_len);
+	btrfs_mark_buffer_dirty(leaf);
+
+	btrfs_free_path(path);
+	return ret;
+}